1
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Hutchison CDM, Perrett S, van Thor JJ. XFEL Beamline Optical Instrumentation for Ultrafast Science. J Phys Chem B 2024; 128:8855-8868. [PMID: 39087627 DOI: 10.1021/acs.jpcb.4c01492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
Free electron lasers operating in the soft and hard X-ray regime provide capabilities for ultrafast science in many areas, including X-ray spectroscopy, diffractive imaging, solution and material scattering, and X-ray crystallography. Ultrafast time-resolved applications in the picosecond, femtosecond, and attosecond regimes are often possible using single-shot experimental configurations. Aside from X-ray pump and X-ray probe measurements, all other types of ultrafast experiments require the synchronized operation of pulsed laser excitation for resonant or nonresonant pumping. This Perspective focuses on the opportunities for the optical control of structural dynamics by applying techniques from nonlinear spectroscopy to ultrafast X-ray experiments. This typically requires the synthesis of two or more optical pulses with full control of pulse and interpulse parameters. To this end, full characterization of the femtosecond optical pulses is also highly desirable. It has recently been shown that two-color and two-pulse femtosecond excitation of fluorescent protein crystals allowed a Tannor-Rice coherent control experiment, performed under characterized conditions. Pulse shaping and the ability to synthesize multicolor and multipulse conditions are highly desirable and would enable XFEL facilities to offer capabilities for structural dynamics. This Perspective will give a summary of examples of the types of experiments that could be achieved, and it will additionally summarize the laser, pulse shaping, and characterization that would be recommended as standard equipment for time-resolved XFEL beamlines, with an emphasis on ultrafast time-resolved serial femtosecond crystallography.
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Affiliation(s)
- Christopher D M Hutchison
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Samuel Perrett
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jasper J van Thor
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, United Kingdom
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2
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Phelps R, Agapaki E, Brechin EK, Johansson JO. Tracking the conical intersection dynamics for the photoinduced Jahn-Teller switch of a Mn(iii) complex. Chem Sci 2024; 15:11956-11964. [PMID: 39092124 PMCID: PMC11290422 DOI: 10.1039/d4sc00145a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 06/24/2024] [Indexed: 08/04/2024] Open
Abstract
Octahedral Mn(iii) ions predominantly exhibit an axially elongated Jahn-Teller (JT) distortion, which is responsible for their large uniaxial magnetic anisotropy. As a result, they are often used in the synthesis of single-molecule magnets (SMMs). Modulation of the JT distortion using femtosecond laser pulses could offer a route to controlling the magnetisation direction, and therefore is promising for the development of data storage devices that work on ultrafast timescales. Photoinduced switching of the distortion from an axially elongated to an axially compressed structure has been demonstrated for various Mn(iii) complexes. However, the dynamics around the region of the conical intersection for the photoinduced JT switch remains unclear. Here, ultrafast transient absorption spectra were recorded for solutions of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)manganese(iii) (Mn(dpm)3) in ethanol to further explore the dynamics of the photoinduced JT switch. We observe the generation of a vibrational wavepacket on the excited state surface, which has a frequency of approximately 155 cm-1 and encompasses a JT-active vibrational mode. This coherent motion is maintained after passage through the conical intersection back to the ground state, which launches wavepackets along the ground state potential energy surface (PES) with frequencies of approximately 180 and 110 cm-1 that we assign to the elongated and compressed state, respectively. Inspection of the relative phases of the frequencies reveals phase shifts that are consistent with a one-mode reaction coordinate, and passes through the conical intersection at 1/4 and 3/4 of the excited state vibrational period. Our results provide direct insights into the non-adiabatic dynamics of Mn(iii) complexes, which can be used to guide the synthesis of optically controlled SMMs.
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Affiliation(s)
- Ryan Phelps
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road EH9 3FJ Edinburgh UK
| | - Eleftheria Agapaki
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road EH9 3FJ Edinburgh UK
| | - Euan K Brechin
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road EH9 3FJ Edinburgh UK
| | - J Olof Johansson
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road EH9 3FJ Edinburgh UK
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3
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Clapham ML, Das A, Douglas CJ, Frontiera RR. Killer Phonon Caught: Femtosecond Stimulated Raman Spectroscopy Identifies Phonon-Induced Control of Photophysics in Rubrene Derivatives. J Am Chem Soc 2024; 146:19939-19950. [PMID: 38991144 DOI: 10.1021/jacs.4c03249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
Molecular reaction coordinates are defined by the interplay of a number of orthogonal nuclear coordinates and are inherently multidimensional for large molecules. Identifying how specific nuclear motions along these reaction coordinates can be used to drive and control chemical processes is a promising approach for the optimization of chemical outcomes and targeted synthetic design. Here, we used femtosecond stimulated Raman spectroscopy (FSRS) to quantify the effects of individual phonon nuclear motions on singlet fission in rubrene derivatives. Rubrene readily undergoes singlet fission and is amendable to chemical derivatization, yet the factors that impact the singlet fission yield are not fully understood. Crystal packing is known to play a significant role in both fission and carrier transport, and thus, we focused on the impact of phonon nuclear motions on the photophysics. We used four halogen-substituted rubrene crystals and successfully identified one specific phonon mode that suppresses singlet fission in these crystals. We used FSRS with single-pulse excitation and double-pulse excitation to coherently amplify each phonon mode and quantify its effects on the excited-state process. We found that coherent amplification of the specific phonon vibration involving twisting of the peripheral phenyl rings and tetracene core motions resulted in less ground-state depletion and fewer triplet state absorption. Our study demonstrated that it is possible to use coherent phonon excitation to influence the photophysical outcome, while also showing that FSRS with double-pulse excitation can be a successful tool for quantifying mode-selective contributions to photophysics.
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Affiliation(s)
- Margaret L Clapham
- Department of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Aritra Das
- Department of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Christopher J Douglas
- Department of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
| | - Renee R Frontiera
- Department of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, Minnesota 55455, United States
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4
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Oberg CP, Spangler LC, Coker DF, Scholes GD. Chirped Laser Pulse Control of Vibronic Wavepackets and Energy Transfer in Phycocyanin 645. J Phys Chem Lett 2024; 15:7125-7132. [PMID: 38959027 DOI: 10.1021/acs.jpclett.4c01455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Photosynthetic organisms use light-harvesting complexes to increase the spectrum of light that they absorb from solar photons. Recent ultrafast spectroscopic studies have revealed that efficient (sub-ps) energy transfer is mediated by vibronic coherence in the phycobiliprotein phycocyanin 645 (PC645). Here, we report studies that employ broadband pump-probe spectroscopy with linearly chirped excitation pulses to further investigate the relationship between vibronic state preparation and energy transfer dynamics in PC645. Negatively chirped pulse excitation is found to enhance wavepackets of a high-frequency mode (1580 cm-1) and increase the rate of downhill energy transfer, while on the other hand, positively chirped pulses suppress these oscillatory features and decrease this rate. Model calculations incorporating the influence of the chirped pump pulse are used to understand its effect on initial state preparation. These results provide mechanistic insight into how the overall nonequilibrium rate of energy transfer is influenced by initial state preparation.
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Affiliation(s)
- Catrina P Oberg
- Department of Chemistry, Princeton University, Washington Rd., Princeton, New Jersey 08544, United States
| | - Leah C Spangler
- Department of Chemistry, Princeton University, Washington Rd., Princeton, New Jersey 08544, United States
| | - David F Coker
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Washington Rd., Princeton, New Jersey 08544, United States
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5
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Mai E, Malakar P, Batignani G, Martinati M, Ruhman S, Scopigno T. Orchestrating Nuclear Dynamics in a Permanganate Doped Crystal with Chirped Pump-Probe Spectroscopy. J Phys Chem Lett 2024; 15:6634-6646. [PMID: 38888442 DOI: 10.1021/acs.jpclett.4c00801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Pump-probe spectroscopy is a powerful tool to investigate light-induced dynamical processes in molecules and solids. Targeting vibrational excitations occurring on the time scales of nuclear motions is challenging, as pulse durations shorter than a vibrational period are needed to initiate the dynamics, and complex experimental schemes are required to isolate weak signatures arising from wavepacket motion in different electronic states. Here, we demonstrate how introducing a temporal delay between the spectral components of femtosecond beams, namely a chirp resulting in the increase of their duration, can counterintuitively boost the desired signals by 2 orders of magnitude. Measuring the time-domain vibrational response of permanganate ions embedded in a KClO4 matrix, we identify an intricate dependence of the vibrational response on pulse chirps and probed wavelength that can be exploited to unveil weak signatures of the doping ions─otherwise dominated by the nonresonant matrix─or to obtain vibrational excitations pertaining only to the excited state, suppressing ground-state contributions.
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Affiliation(s)
- Emanuele Mai
- Dipartimento di Fisica, Sapienza, Universitá di Roma, Roma I-00185, Italy
- Istituto Italiano di Tecnologia, Center for Life Nano Science @Sapienza, Roma I-00161, Italy
| | - Partha Malakar
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Giovanni Batignani
- Dipartimento di Fisica, Sapienza, Universitá di Roma, Roma I-00185, Italy
- Istituto Italiano di Tecnologia, Center for Life Nano Science @Sapienza, Roma I-00161, Italy
| | - Miles Martinati
- Dipartimento di Fisica, Sapienza, Universitá di Roma, Roma I-00185, Italy
| | - Sanford Ruhman
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Tullio Scopigno
- Dipartimento di Fisica, Sapienza, Universitá di Roma, Roma I-00185, Italy
- Graphene Laboratories, Istituto Italiano di Tecnologia, Genova I-16163, Italy
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6
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Green D, Bressan G, Heisler IA, Meech SR, Jones GA. Vibrational coherences in half-broadband 2D electronic spectroscopy: Spectral filtering to identify excited state displacements. J Chem Phys 2024; 160:234104. [PMID: 38884412 DOI: 10.1063/5.0214023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 06/03/2024] [Indexed: 06/18/2024] Open
Abstract
Vibrational coherences in ultrafast pump-probe (PP) and 2D electronic spectroscopy (2DES) provide insights into the excited state dynamics of molecules. Femtosecond coherence spectra and 2D beat maps yield information about displacements of excited state surfaces for key vibrational modes. Half-broadband 2DES uses a PP configuration with a white light continuum probe to extend the detection range and resolve vibrational coherences in the excited state absorption (ESA). However, the interpretation of these spectra is difficult as they are strongly dependent on the spectrum of the pump laser and the relative displacement of the excited states along the vibrational coordinates. We demonstrate the impact of these convoluting factors for a model based upon cresyl violet. A careful consideration of the position of the pump spectrum can be a powerful tool in resolving the ESA coherences to gain insights into excited state displacements. This paper also highlights the need for caution in considering the spectral window of the pulse when interpreting these spectra.
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Affiliation(s)
- Dale Green
- Physics, Faculty of Science, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Giovanni Bressan
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Ismael A Heisler
- Instituto de Física, Universidade Federal do Rio Grande do Sul, 91509-900 Porto Alegre, RS, Brazil
| | - Stephen R Meech
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
| | - Garth A Jones
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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7
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Ghosh P, Alvertis AM, Chowdhury R, Murto P, Gillett AJ, Dong S, Sneyd AJ, Cho HH, Evans EW, Monserrat B, Li F, Schnedermann C, Bronstein H, Friend RH, Rao A. Decoupling excitons from high-frequency vibrations in organic molecules. Nature 2024; 629:355-362. [PMID: 38720042 PMCID: PMC11078737 DOI: 10.1038/s41586-024-07246-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 02/27/2024] [Indexed: 05/12/2024]
Abstract
The coupling of excitons in π-conjugated molecules to high-frequency vibrational modes, particularly carbon-carbon stretch modes (1,000-1,600 cm-1) has been thought to be unavoidable1,2. These high-frequency modes accelerate non-radiative losses and limit the performance of light-emitting diodes, fluorescent biomarkers and photovoltaic devices. Here, by combining broadband impulsive vibrational spectroscopy, first-principles modelling and synthetic chemistry, we explore exciton-vibration coupling in a range of π-conjugated molecules. We uncover two design rules that decouple excitons from high-frequency vibrations. First, when the exciton wavefunction has a substantial charge-transfer character with spatially disjoint electron and hole densities, we find that high-frequency modes can be localized to either the donor or acceptor moiety, so that they do not significantly perturb the exciton energy or its spatial distribution. Second, it is possible to select materials such that the participating molecular orbitals have a symmetry-imposed non-bonding character and are, thus, decoupled from the high-frequency vibrational modes that modulate the π-bond order. We exemplify both these design rules by creating a series of spin radical systems that have very efficient near-infrared emission (680-800 nm) from charge-transfer excitons. We show that these systems have substantial coupling to vibrational modes only below 250 cm-1, frequencies that are too low to allow fast non-radiative decay. This enables non-radiative decay rates to be suppressed by nearly two orders of magnitude in comparison to π-conjugated molecules with similar bandgaps. Our results show that losses due to coupling to high-frequency modes need not be a fundamental property of these systems.
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Affiliation(s)
- Pratyush Ghosh
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Antonios M Alvertis
- KBR, Inc., NASA Ames Research Center, Moffett Field, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Petri Murto
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | - Shengzhi Dong
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, China
| | | | - Hwan-Hee Cho
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Emrys W Evans
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Department of Chemistry, Swansea University, Swansea, UK
| | - Bartomeu Monserrat
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK
| | - Feng Li
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, China
| | | | - Hugo Bronstein
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | | | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
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8
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Rode AJ, Arpin PC, Turner DB. Theoretical model of femtosecond coherence spectroscopy of vibronic excitons in molecular aggregates. J Chem Phys 2024; 160:164101. [PMID: 38647298 DOI: 10.1063/5.0200570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024] Open
Abstract
When used as pump pulses in transient absorption spectroscopy measurements, femtosecond laser pulses can produce oscillatory signals known as quantum beats. The quantum beats arise from coherent superpositions of the states of the sample and are best studied in the Fourier domain using Femtosecond Coherence Spectroscopy (FCS), which consists of one-dimensional amplitude and phase plots of a specified oscillation frequency as a function of the detection frequency. Prior works have shown ubiquitous amplitude nodes and π phase shifts in FCS from excited-state vibrational wavepackets in monomer samples. However, the FCS arising from vibronic-exciton states in molecular aggregates have not been studied theoretically. Here, we use a model of vibronic-exciton states in molecular dimers based on displaced harmonic oscillators to simulate FCS for dimers in two important cases. Simulations reveal distinct spectral signatures of excited-state vibronic-exciton coherences in molecular dimers that may be used to distinguish them from monomer vibrational coherences. A salient result is that, for certain relative orientations of the transition dipoles, the key resonance condition between the electronic coupling and the frequency of the vibrational mode may yield strong enhancement of the quantum-beat amplitude and, perhaps, also cause a significant decrease of the oscillation frequency to a value far lower than the vibrational frequency. Future studies using these results will lead to new insights into the excited-state coherences generated in photosynthetic pigment-protein complexes.
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Affiliation(s)
- Alexander J Rode
- Micron School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
| | - Paul C Arpin
- Department of Physics, California State University, Chico, Chico, California 95929, USA
| | - Daniel B Turner
- Micron School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, USA
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9
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Mann JG, He F, Akkerman QA, Debnath T, Feldmann J. A Bound Exciton Resonance Modulated by Bulk and Localized Coherent Phonons in Double Perovskites. J Phys Chem Lett 2024; 15:2169-2176. [PMID: 38373052 DOI: 10.1021/acs.jpclett.3c03443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Optically excited electronic excitations are coupled to the soft and polar halide perovskite lattice, generating coherent phonons after subpicosecond interband laser-excitation. In Ag-based halide double perovskites, Ag-vacancies can bind free excitons, resulting in a pronounced bound exciton resonance. Here, we report the detection of three modulation frequencies corresponding to coherent phonons in Ag-based double perovskite nanocrystals at distinct spectral positions at the bound exciton resonance. Two of them are found in oscillatory spectral shifts of the bound exciton resonance and are identified as Cs- and Br-related bulk phonons. Surprisingly, a third frequency is observed as an intensity modulation. We argue that this amplitude oscillation is a consequence of an optically generated vibronic wave packet localized at a Ag-vacancy. Consequently, the localized coherent phonon modulates the giant oscillator strength of the bound exciton. This optically induced and spatially localized lattice shaking could potentially be useful for initiating photochemical reactions with atomic precision.
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Affiliation(s)
- Julian G Mann
- Chair for Photonics and Optoelectronics, Nano-Institute Munich and Department of Physics, Ludwig-Maximilians-Universität (LMU), Königinstr. 10, 80539 Munich, Germany
| | - Fei He
- Chair for Photonics and Optoelectronics, Nano-Institute Munich and Department of Physics, Ludwig-Maximilians-Universität (LMU), Königinstr. 10, 80539 Munich, Germany
| | - Quinten A Akkerman
- Chair for Photonics and Optoelectronics, Nano-Institute Munich and Department of Physics, Ludwig-Maximilians-Universität (LMU), Königinstr. 10, 80539 Munich, Germany
| | - Tushar Debnath
- Chair for Photonics and Optoelectronics, Nano-Institute Munich and Department of Physics, Ludwig-Maximilians-Universität (LMU), Königinstr. 10, 80539 Munich, Germany
- Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
- Nano Physical Spectroscopy Group, Department of Chemistry, School of Natural Sciences, Shiv Nadar Institution of Eminence, Delhi NCR, Uttar Pradesh 201314, India
| | - Jochen Feldmann
- Chair for Photonics and Optoelectronics, Nano-Institute Munich and Department of Physics, Ludwig-Maximilians-Universität (LMU), Königinstr. 10, 80539 Munich, Germany
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10
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Qiang Y, Sun K, Palacino-González E, Shen K, Rao BJ, Gelin MF, Zhao Y. Probing avoided crossings and conical intersections by two-pulse femtosecond stimulated Raman spectroscopy: Theoretical study. J Chem Phys 2024; 160:054107. [PMID: 38341700 DOI: 10.1063/5.0186583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 01/15/2024] [Indexed: 02/13/2024] Open
Abstract
This study leverages two-pulse femtosecond stimulated Raman spectroscopy (2FSRS) to characterize molecular systems with avoided crossings (ACs) and conical intersections (CIs) in their low-lying excited electronic states. By simulating 2FSRS spectra of microscopically inspired ACs and CIs models, we demonstrate that 2FSRS not only delivers valuable information on the molecular parameters characterizing ACs and CIs but also helps distinguish between these two systems.
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Affiliation(s)
- Yijia Qiang
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Kewei Sun
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Elisa Palacino-González
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Kaijun Shen
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - B Jayachander Rao
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Maxim F Gelin
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Yang Zhao
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
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11
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Cai MR, Zhang X, Cheng ZQ, Yan TF, Dong H. Cross-phase modulation in two-dimensional spectroscopy. OPTICS EXPRESS 2024; 32:2929-2941. [PMID: 38297529 DOI: 10.1364/oe.503686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 12/31/2023] [Indexed: 02/02/2024]
Abstract
Developing from transient absorption (TA) spectroscopy, two-dimensional (2D) spectroscopy with pump-probe geometry has emerged as a versatile approach for alleviating the difficulty in implementing 2D spectroscopy with other geometries. However, the presence of cross-phase modulation (XPM) in TA spectroscopy introduces significant spectral distortions, particularly when the pump and probe pulses overlap. We demonstrate that this phenomenon is extended to the 2D spectroscopy with pump-probe geometry and the XPM is induced by the interference of the two pump pulses. We present the oscillatory behavior of XPM in the 2D spectrum and its displacement with respect to the waiting time delay through both experimental measurements and numerical simulations. Additionally, we explore the influence of probe pulse chirp on XPM and discover that by compressing the chirp, the impact of XPM on the desired signal can be reduced.
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12
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Timmer D, Lünemann DC, Riese S, Sio AD, Lienau C. Full visible range two-dimensional electronic spectroscopy with high time resolution. OPTICS EXPRESS 2024; 32:835-847. [PMID: 38175103 DOI: 10.1364/oe.511906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024]
Abstract
Two-dimensional electronic spectroscopy (2DES) is a powerful method to study coherent and incoherent interactions and dynamics in complex quantum systems by correlating excitation and detection energies in a nonlinear spectroscopy experiment. Such dynamics can be probed with a time resolution limited only by the duration of the employed laser pulses and in a spectral range defined by the pulse spectrum. In the blue spectral range (<500 nm), the generation of sufficiently broadband ultrashort pulses with pulse durations of 10 fs or less has been challenging so far. Here, we present a 2DES setup based on a hollow-core fiber supercontinuum covering the full visible range (400-700 nm). Pulse compression via custom-made chirped mirrors yields a time resolution of <10 fs. The broad spectral coverage, in particular the extension of the pulse spectra into the blue spectral range, unlocks new possibilities for coherent investigations of blue-light absorbing and multichromophoric compounds, as demonstrated by a 2DES measurement of chlorophyll a.
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13
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van Stokkum IHM, Weißenborn J, Weigand S, Snellenburg JJ. Pyglotaran: a lego-like Python framework for global and target analysis of time-resolved spectra. Photochem Photobiol Sci 2023; 22:2413-2431. [PMID: 37523126 DOI: 10.1007/s43630-023-00460-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 07/12/2023] [Indexed: 08/01/2023]
Abstract
The dynamics of molecular systems can be studied with time-resolved spectroscopy combined with model-based analysis. A Python framework for global and target analysis of time-resolved spectra is introduced with the help of three case studies. The first study, concerning broadband absorption of intersystem crossing in 4-thiothymidine, demonstrates the framework's ability to resolve vibrational wavepackets with a time resolution of ≈10 fs using damped oscillations and their associated spectra and phases. Thereby, a parametric description of the "coherent artifact" is crucial. The second study addresses multichromophoric systems composed of two perylene bisimide chromophores. Here, pyglotaran's guidance spectra and lego-like model composition enable the integration of spectral and kinetic properties of the parent chromophores, revealing a loss process, the undesired production of a radical pair, that reduces the light harvesting efficiency. In the third, time-resolved emission case study of whole photosynthetic cells, a megacomplex containing ≈500 chromophores of five different types is described by a combination of the kinetic models for its elements. As direct fitting of the data by theoretical simulation is unfeasible, our global and target analysis methodology provides a useful 'middle ground' where the theoretical description and the fit of the experimental data can meet. The pyglotaran framework enables the lego-like creation of kinetic models through its modular design and seamless integration with the rich Python ecosystem, particularly Jupyter notebooks. With extensive documentation and a robust validation framework, pyglotaran ensures accessibility and reliability for researchers, serving as an invaluable tool for understanding complex molecular systems.
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Affiliation(s)
- Ivo H M van Stokkum
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
| | - Jörn Weißenborn
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Sebastian Weigand
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
- Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, 10623, Berlin, Germany
| | - Joris J Snellenburg
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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14
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Phelps R, Etcheverry-Berrios A, Brechin EK, Johansson JO. Equatorial restriction of the photoinduced Jahn-Teller switch in Mn(iii)-cyclam complexes. Chem Sci 2023; 14:6621-6630. [PMID: 37350826 PMCID: PMC10284123 DOI: 10.1039/d3sc01506h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/25/2023] [Indexed: 06/24/2023] Open
Abstract
Ultrafast transient absorption spectra were recorded for solutions of [MnIII(cyclam)(H2O)(OTf)][OTf]2 (cyclam = 1,4,8,11-tetraazacyclotetradecane and OTf = trifluoromethanesulfonate) in water to explore the possibility to restrict the equatorial expansion following photoexcitation of the dxy ← dz2 electronic transition, often resulting in a switch from axial to equatorial Jahn-Teller distortion in MnIII complexes. Strong oscillations were observed in the excited state absorption signal and were attributed to an excited state wavepacket. The structural rigidity of the cyclam ligand causes a complex reaction coordinate with frequencies of 333, 368, 454 and 517 cm-1, and a significantly shorter compressed-state lifetime compared to other MnIII complexes with less restricted equatorial ligands. Complementary density functional theory quantum chemistry calculations indicate a switch from an axially elongated to a compressed structure in the first excited quintet state Q1, which is accompanied by a modulation of the axial tilt angle. Computed harmonic frequencies for the axial stretching mode (∼379 cm-1) and the equatorial expansions (∼410 and 503 cm-1) of the Q1 state agree well with the observed coherences and indicate that the axial bond length contraction is significantly larger than the equatorial expansion, which implies a successful restriction of the wavepacket motion. The weak oscillation observed around 517 cm-1 is assigned to a see-saw motion of the axial tilt (predicted ∼610 cm-1). The results provide insights into the structural perturbations to the molecular evolution along excited state potential energy surfaces of MnIII octahedral complexes and can be used to guide the synthesis of optically controlled MnIII-based single-molecule magnets.
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Affiliation(s)
- Ryan Phelps
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road EH9 3FJ Edinburgh UK
| | | | - Euan K Brechin
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road EH9 3FJ Edinburgh UK
| | - J Olof Johansson
- EaStCHEM School of Chemistry, University of Edinburgh David Brewster Road EH9 3FJ Edinburgh UK
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15
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Luo Y, Martin-Jimenez A, Pisarra M, Martin F, Garg M, Kern K. Imaging and controlling coherent phonon wave packets in single graphene nanoribbons. Nat Commun 2023; 14:3484. [PMID: 37311753 DOI: 10.1038/s41467-023-39239-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 06/06/2023] [Indexed: 06/15/2023] Open
Abstract
The motion of atoms is at the heart of any chemical or structural transformation in molecules and materials. Upon activation of this motion by an external source, several (usually many) vibrational modes can be coherently coupled, thus facilitating the chemical or structural phase transformation. These coherent dynamics occur on the ultrafast timescale, as revealed, e.g., by nonlocal ultrafast vibrational spectroscopic measurements in bulk molecular ensembles and solids. Tracking and controlling vibrational coherences locally at the atomic and molecular scales is, however, much more challenging and in fact has remained elusive so far. Here, we demonstrate that the vibrational coherences induced by broadband laser pulses on a single graphene nanoribbon (GNR) can be probed by femtosecond coherent anti-Stokes Raman spectroscopy (CARS) when performed in a scanning tunnelling microscope (STM). In addition to determining dephasing (~440 fs) and population decay times (~1.8 ps) of the generated phonon wave packets, we are able to track and control the corresponding quantum coherences, which we show to evolve on time scales as short as ~70 fs. We demonstrate that a two-dimensional frequency correlation spectrum unequivocally reveals the quantum couplings between different phonon modes in the GNR.
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Affiliation(s)
- Yang Luo
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Alberto Martin-Jimenez
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
| | - Michele Pisarra
- INFN-LNF, Gruppo Collegato di Cosenza, Via P. Bucci, cubo 31C, 87036, Rende (CS), Italy
| | - Fernando Martin
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nano), Faraday 9, Cantoblanco, 28049, Madrid, Spain
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Manish Garg
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
| | - Klaus Kern
- Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
- Institut de Physique, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
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16
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Solaris J, Krueger TD, Chen C, Fang C. Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red. Molecules 2023; 28:3506. [PMID: 37110741 PMCID: PMC10144053 DOI: 10.3390/molecules28083506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Proton transfer processes of organic molecules are key to charge transport and photoprotection in biological systems. Among them, excited-state intramolecular proton transfer (ESIPT) reactions are characterized by quick and efficient charge transfer within a molecule, resulting in ultrafast proton motions. The ESIPT-facilitated interconversion between two tautomers (PS and PA) comprising the tree fungal pigment Draconin Red in solution was investigated using a combination of targeted femtosecond transient absorption (fs-TA) and excited-state femtosecond stimulated Raman spectroscopy (ES-FSRS) measurements. Transient intensity (population and polarizability) and frequency (structural and cooling) dynamics of -COH rocking and -C=C, -C=O stretching modes following directed stimulation of each tautomer elucidate the excitation-dependent relaxation pathways, particularly the bidirectional ESIPT progression out of the Franck-Condon region to the lower-lying excited state, of the intrinsically heterogeneous chromophore in dichloromethane solvent. A characteristic overall excited-state PS-to-PA transition on the picosecond timescale leads to a unique "W"-shaped excited-state Raman intensity pattern due to dynamic resonance enhancement with the Raman pump-probe pulse pair. The ability to utilize quantum mechanics calculations in conjunction with steady-state electronic absorption and emission spectra to induce disparate excited-state populations in an inhomogeneous mixture of similar tautomers has broad implications for the modeling of potential energy surfaces and delineation of reaction mechanisms in naturally occurring chromophores. Such fundamental insights afforded by in-depth analysis of ultrafast spectroscopic datasets are also beneficial for future development of sustainable materials and optoelectronics.
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17
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Kumar A, Malevich P, Mewes L, Wu S, Barham JP, Hauer J. Transient absorption spectroscopy based on uncompressed hollow core fiber white light proves pre-association between a radical ion photocatalyst and substrate. J Chem Phys 2023; 158:144201. [PMID: 37061463 DOI: 10.1063/5.0142225] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023] Open
Abstract
We present a hollow-core fiber (HCF) based transient absorption experiment, with capabilities beyond common titanium:sapphire based setups. By spectral filtering of the HCF spectrum, we provide pump pulses centered at 425 nm with several hundred nJ of pulse energy at the sample position. By employing the red edge of the HCF output for seeding CaF2, we obtain smooth probing spectra in the range between 320 and 900 nm. We demonstrate the capabilities of our experiment by following the ultrafast relaxation dynamics of a radical cationic photocatalyst to prove its pre-association with an arene substrate, a phenomenon that was not detectable previously by steady-state spectroscopic techniques. The detected preassembly rationalizes the successful participation of radical ionic photocatalysts in single electron transfer reactions, a notion that has been subject to controversy in recent years.
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Affiliation(s)
- Ajeet Kumar
- Department of Chemistry and Catalysis Research Center (CRC), School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Pavel Malevich
- Department of Chemistry and Catalysis Research Center (CRC), School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Lars Mewes
- Department of Chemistry and Catalysis Research Center (CRC), School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Shangze Wu
- Universität Regensburg, Fakultät für Chemie und Pharmazie, 93040 Regensburg, Germany
| | - Joshua P Barham
- Universität Regensburg, Fakultät für Chemie und Pharmazie, 93040 Regensburg, Germany
| | - Jürgen Hauer
- Department of Chemistry and Catalysis Research Center (CRC), School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
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18
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Wei YC, Chen BH, Ye RS, Huang HW, Su JX, Lin CY, Hodgkiss J, Hsu LY, Chi Y, Chen K, Lu CH, Yang SD, Chou PT. Excited-State THz Vibrations in Aggregates of Pt II Complexes Contribute to the Enhancement of Near-Infrared Emission Efficiencies. Angew Chem Int Ed Engl 2023; 62:e202300815. [PMID: 36825300 DOI: 10.1002/anie.202300815] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/23/2023] [Accepted: 02/23/2023] [Indexed: 02/25/2023]
Abstract
The exploration of deactivation mechanisms for near-infrared(NIR)-emissive organic molecules has been a key issue in chemistry, materials science and molecular biology. In this study, based on transient absorption spectroscopy and transient grating photoluminescence spectroscopy, we demonstrate that the aggregated PtII complex 4H (efficient NIR emitter) exhibits collective out-of-plane motions with a frequency of 32 cm-1 (0.96 THz) in the excited states. Importantly, similar THz characteristics were also observed in analogous PtII complexes with prominent NIR emission efficiency. The conservation of THz motions enables excited-state deactivation to proceed along low-frequency vibrational coordinates, contributing to the suppression of nonradiative decay and remarkable NIR emission. These novel results highlight the significance of excited-state vibrations in nonradiative processes, which serve as a benchmark for improving device performance.
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Affiliation(s)
- Yu-Chen Wei
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
| | - Bo-Han Chen
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Ren-Siang Ye
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Hsing-Wei Huang
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Jia-Xuan Su
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Chao-Yang Lin
- Robinson Research Institute, Faculty of Engineering, Victoria University of Wellington, Wellington, 6012, New Zealand
| | - Justin Hodgkiss
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, 6010, New Zealand
| | - Lian-Yan Hsu
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan
- National Center for Theoretical Sciences, Taipei, 10617, Taiwan
| | - Yun Chi
- Department of Materials Science and Engineering, Department of Chemistry, and Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong SAR, Hong Kong
| | - Kai Chen
- Robinson Research Institute, Faculty of Engineering, Victoria University of Wellington, Wellington, 6012, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, 6010, New Zealand
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin, 9016, New Zealand
| | - Chih-Hsuan Lu
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Shang-Da Yang
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan
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19
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Song J, Peng Y, Shen L, Sun J, Luo G, Xu X, Xu J, Leng Y. High-power femtosecond regenerative amplifier based on Yb:CaYAlO 4 dual-crystal configuration. OPTICS LETTERS 2023; 48:1395-1398. [PMID: 36946936 DOI: 10.1364/ol.484843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
A thermal lens insensitive regenerative amplifier (RA) with a dual Yb:CaYAlO4 (Yb:CYA) crystal configuration for extending gain spectra is demonstrated for the first time, to the best of our knowledge. By orthogonalizing the orientation of two a-cut Yb:CYA crystals in one RA, the Q switched spectrum with a full width at half maximum of 15.4 nm is generated, which is 1.5 and 1.6 times of the Q switched spectral bandwidth with π- and σ-polarization, respectively. With chirped pulses injection, this RA can deliver laser pulses with an average power exceeding 10 W at the repetition rate of 20-800 kHz and pulse energy of 1.5 mJ at 1 kHz. This is the highest average power from the Yb:CYA RA to the best of our knowledge. Finally, compressed pulses of 163 fs with 92% overall efficiency are realized. Thanks to the heat insensitive cavity design and excellent thermodynamic properties of the Yb:CYA crystal, the output laser beam is close to the diffraction limit with an M2 value of 1.07 × 1.07.
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20
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Wei Y, Chen B, Ye R, Huang H, Su J, Lin C, Hodgkiss J, Hsu L, Chi Y, Chen K, Lu C, Yang S, Chou P. Excited‐State THz Vibrations in Aggregates of Pt
II
Complexes Contribute to the Enhancement of Near‐Infrared Emission Efficiencies**. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/ange.202300815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Affiliation(s)
- Yu‐Chen Wei
- Department of Chemistry National Taiwan University Taipei 10617 Taiwan
- Institute of Atomic and Molecular Sciences Academia Sinica Taipei 10617 Taiwan
| | - Bo‐Han Chen
- Institute of Photonics Technologies National Tsing Hua University Hsinchu 30013 Taiwan
| | - Ren‐Siang Ye
- Institute of Photonics Technologies National Tsing Hua University Hsinchu 30013 Taiwan
| | - Hsing‐Wei Huang
- Institute of Photonics Technologies National Tsing Hua University Hsinchu 30013 Taiwan
| | - Jia‐Xuan Su
- Institute of Photonics Technologies National Tsing Hua University Hsinchu 30013 Taiwan
| | - Chao‐Yang Lin
- Robinson Research Institute Faculty of Engineering Victoria University of Wellington Wellington 6012 New Zealand
| | - Justin Hodgkiss
- MacDiarmid Institute for Advanced Materials and Nanotechnology Wellington 6010 New Zealand
| | - Lian‐Yan Hsu
- Department of Chemistry National Taiwan University Taipei 10617 Taiwan
- Institute of Atomic and Molecular Sciences Academia Sinica Taipei 10617 Taiwan
- National Center for Theoretical Sciences Taipei 10617 Taiwan
| | - Yun Chi
- Department of Materials Science and Engineering Department of Chemistry and Center of Super-Diamond and Advanced Films (COSDAF) City University of Hong Kong Hong Kong SAR Hong Kong
| | - Kai Chen
- Robinson Research Institute Faculty of Engineering Victoria University of Wellington Wellington 6012 New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology Wellington 6010 New Zealand
- The Dodd-Walls Centre for Photonic and Quantum Technologies Dunedin 9016 New Zealand
| | - Chih‐Hsuan Lu
- Institute of Photonics Technologies National Tsing Hua University Hsinchu 30013 Taiwan
| | - Shang‐Da Yang
- Institute of Photonics Technologies National Tsing Hua University Hsinchu 30013 Taiwan
| | - Pi‐Tai Chou
- Department of Chemistry National Taiwan University Taipei 10617 Taiwan
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21
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Bailey-Darland S, Krueger TD, Fang C. Ultrafast Spectroscopies of Nitrophenols and Nitrophenolates in Solution: From Electronic Dynamics and Vibrational Structures to Photochemical and Environmental Implications. Molecules 2023; 28:601. [PMID: 36677656 PMCID: PMC9866910 DOI: 10.3390/molecules28020601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/27/2022] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Nitrophenols are a group of small organic molecules with significant environmental implications from the atmosphere to waterways. In this work, we investigate a series of nitrophenols and nitrophenolates, with the contrasting ortho-, meta-, and para-substituted nitro group to the phenolic hydroxy or phenolate oxygen site (2/3/4NP or NP-), implementing a suite of steady-state and time-resolved spectroscopic techniques that include UV/Visible spectroscopy, femtosecond transient absorption (fs-TA) spectroscopy with probe-dependent and global analysis, and femtosecond stimulated Raman spectroscopy (FSRS), aided by quantum calculations. The excitation-dependent (400 and 267 nm) electronic dynamics in water and methanol, for six protonated or deprotonated nitrophenol molecules (three regioisomers in each set), enable a systematic investigation of the excited-state dynamics of these functional "nanomachines" that can undergo nitro-group twisting (as a rotor), excited-state intramolecular or intermolecular proton transfer (donor-acceptor, ESIPT, or ESPT), solvation, and cooling (chromophore) events on molecular timescales. In particular, the meta-substituted compound 3NP or 3NP- exhibits the strongest charge-transfer character with FSRS signatures (e.g., C-N peak frequency), and thus, does not favor nitroaromatic twist in the excited state, while the ortho-substituted compound 2NP can undergo ESIPT in water and likely generate nitrous acid (HONO) after 267 nm excitation. The delineated mechanistic insights into the nitro-substituent-location-, protonation-, solvent-, and excitation-wavelength-dependent effects on nitrophenols, in conjunction with the ultraviolet-light-induced degradation of 2NP in water, substantiates an appealing discovery loop to characterize and engineer functional molecules for environmental applications.
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22
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Boeije Y, Olivucci M. From a one-mode to a multi-mode understanding of conical intersection mediated ultrafast organic photochemical reactions. Chem Soc Rev 2023; 52:2643-2687. [PMID: 36970950 DOI: 10.1039/d2cs00719c] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
This review discusses how ultrafast organic photochemical reactions are controlled by conical intersections, highlighting that decay to the ground-state at multiple points of the intersection space results in their multi-mode character.
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Affiliation(s)
- Yorrick Boeije
- Van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Massimo Olivucci
- Chemistry Department, University of Siena, Via Aldo Moro n. 2, 53100 Siena, Italy
- Chemistry Department, Bowling Green State University, Overman Hall, Bowling Green, Ohio 43403, USA
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23
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Zhang Q, Li J, Wen J, Li W, Chen X, Zhang Y, Sun J, Yan X, Hu M, Wu G, Yuan K, Guo H, Yang X. Simultaneous capturing phonon and electron dynamics in MXenes. Nat Commun 2022; 13:7900. [PMID: 36550116 PMCID: PMC9780317 DOI: 10.1038/s41467-022-35605-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
Plasmonic MXenes are of particular interest, because of their unique electron and phonon structures and multiple surface plasmon effects, which are different from traditional plasmonic materials. However, to date, how electronic energy damp to lattice vibrations (phonons) in MXenes has not been unraveled. Here, we employed ultrafast broadband impulsive vibrational spectroscopy to identify the energy damping channels in MXenes (Ti3C2Tx and Mo2CTx). Distinctive from the well-known damping pathways, our results demonstrate a different energy damping channel, in which the Ti3C2Tx plasmonic electron energy transfers to coherent phonons by nonthermal electron mediation after Landau damping, without involving electron-electron scattering. Moreover, electrons are observed to strongly couple with A1g mode (~60 fs, 85-100%) and weakly couple with Eg mode (1-2 ps, 0-15%). Our results provide new insight into the electron-phonon interaction in MXenes, which allows the design of materials enabling efficient manipulation of electron transport and energy conversion.
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Affiliation(s)
- Qi Zhang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, P.R. China
| | - Jiebo Li
- Institute of Medical Photonics, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, P.R. China.
| | - Jiao Wen
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, P.R. China
| | - Wei Li
- GuSu Laboratory of Materials, Suzhou, 215123, Jiangsu, China
| | - Xin Chen
- GuSu Laboratory of Materials, Suzhou, 215123, Jiangsu, China
| | - Yifan Zhang
- Institute of Medical Photonics, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, P.R. China
| | - Jingyong Sun
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, P.R. China
| | - Xin Yan
- School of Mechanical Engineering and Automation, Beihang University, Beijing, 100191, P. R. China
| | - Mingjun Hu
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, P.R. China
| | - Guorong Wu
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, P.R. China
| | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, P.R. China.
- Hefei National Laboratory, Hefei, 230088, China.
| | - Hongbo Guo
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, P.R. China.
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, P.R. China
- Hefei National Laboratory, Hefei, 230088, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen, 518055, P. R. China
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24
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Absolute excited state molecular geometries revealed by resonance Raman signals. Nat Commun 2022; 13:7770. [PMID: 36522323 PMCID: PMC9755279 DOI: 10.1038/s41467-022-35099-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 11/18/2022] [Indexed: 12/23/2022] Open
Abstract
Ultrafast reactions activated by light absorption are governed by multidimensional excited-state (ES) potential energy surfaces (PESs), which describe how the molecular potential varies with the nuclear coordinates. ES PESs ad-hoc displaced with respect to the ground state can drive subtle structural rearrangements, accompanying molecular biological activity and regulating physical/chemical properties. Such displacements are encoded in the Franck-Condon overlap integrals, which in turn determine the resonant Raman response. Conventional spectroscopic approaches only access their absolute value, and hence cannot determine the sense of ES displacements. Here, we introduce a two-color broadband impulsive Raman experimental scheme, to directly measure complex Raman excitation profiles along desired normal modes. The key to achieve this task is in the signal linear dependence on the Frank-Condon overlaps, brought about by non-degenerate resonant probe and off-resonant pump pulses, which ultimately enables time-domain sensitivity to the phase of the stimulated vibrational coherences. Our results provide the tool to determine the magnitude and the sensed direction of ES displacements, unambiguously relating them to the ground state eigenvectors reference frame.
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25
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Timmer D, Zheng F, Gittinger M, Quenzel T, Lünemann DC, Winte K, Zhang Y, Madjet ME, Zablocki J, Lützen A, Zhong JH, De Sio A, Frauenheim T, Tretiak S, Lienau C. Charge Delocalization and Vibronic Couplings in Quadrupolar Squaraine Dyes. J Am Chem Soc 2022; 144:19150-19162. [PMID: 36206456 DOI: 10.1021/jacs.2c08682] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Squaraines are prototypical quadrupolar charge-transfer chromophores that have recently attracted much attention as building blocks for solution-processed photovoltaics, fluorescent probes with large two-photon absorption cross sections, and aggregates with large circular dichroism. Their optical properties are often rationalized in terms of phenomenological essential state models, considering the coupling of two zwitterionic excited states to a neutral ground state. As a result, optical transitions to the lowest S1 excited state are one-photon allowed, whereas the next higher S2 state can only be accessed by two-photon transitions. A further implication of these models is a substantial reduction of vibronic coupling to the ubiquitous high-frequency vinyl-stretching modes of organic materials. Here, we combine time-resolved vibrational spectroscopy, two-dimensional electronic spectroscopy, and quantum-chemical simulations to test and rationalize these predictions for nonaggregated molecules. We find small Huang-Rhys factors below 0.01 for the high-frequency, 1500 cm-1 modes in particular, as well as a noticeable reduction for those of lower frequency modes in general for the electronic S0 → S1 transition. The two-photon allowed state S2 is well separated energetically from S1 and has weak vibronic signatures as well. Thus, the resulting pronounced concentration of the oscillator strength in a narrow region relevant to the lowest electronic transition makes squaraines and their aggregates exceptionally interesting for strong and ultrastrong coupling of excitons to localized light modes in external resonators with chiral properties that can largely be controlled by the molecular architecture.
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Affiliation(s)
- Daniel Timmer
- Institut für Physik, Carl von Ossietzky Universität, Oldenburg26129, Germany
| | - Fulu Zheng
- Bremen Center for Computational Materials Science, University of Bremen, Bremen28359, Germany
| | - Moritz Gittinger
- Institut für Physik, Carl von Ossietzky Universität, Oldenburg26129, Germany
| | - Thomas Quenzel
- Institut für Physik, Carl von Ossietzky Universität, Oldenburg26129, Germany
| | - Daniel C Lünemann
- Institut für Physik, Carl von Ossietzky Universität, Oldenburg26129, Germany
| | - Katrin Winte
- Institut für Physik, Carl von Ossietzky Universität, Oldenburg26129, Germany
| | - Yu Zhang
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico87545, United States
| | - Mohamed E Madjet
- Bremen Center for Computational Materials Science, University of Bremen, Bremen28359, Germany
| | - Jennifer Zablocki
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Bonn53121, Germany
| | - Arne Lützen
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Bonn53121, Germany
| | - Jin-Hui Zhong
- Institut für Physik, Carl von Ossietzky Universität, Oldenburg26129, Germany.,Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong518055, China
| | - Antonietta De Sio
- Institut für Physik, Carl von Ossietzky Universität, Oldenburg26129, Germany.,Center for Nanoscale Dynamics (CeNaD), Carl von Ossietzky Universität, Oldenburg26129, Germany
| | - Thomas Frauenheim
- Bremen Center for Computational Materials Science, University of Bremen, Bremen28359, Germany.,Beijing Computational Science Research Center (CSRC), Beijing100193, China.,Shenzhen Computational Science and Applied Research (CSAR) Institute, Shenzhen518110, China
| | - Sergei Tretiak
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico87545, United States
| | - Christoph Lienau
- Institut für Physik, Carl von Ossietzky Universität, Oldenburg26129, Germany.,Center for Nanoscale Dynamics (CeNaD), Carl von Ossietzky Universität, Oldenburg26129, Germany.,Forschungszentrum Neurosensorik, Carl von Ossietzky Universität, Oldenburg26129, Germany
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26
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Tao W, Zhu L, Li K, Chen C, Chen Y, Li Y, Li X, Tang J, Shang H, Zhu H. Coupled Electronic and Anharmonic Structural Dynamics for Carrier Self-Trapping in Photovoltaic Antimony Chalcogenides. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202154. [PMID: 35754307 PMCID: PMC9443444 DOI: 10.1002/advs.202202154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/20/2022] [Indexed: 06/15/2023]
Abstract
V-VI antimony chalcogenide semiconductors have shown exciting potentials for thin film photovoltaic applications. However, their solar cell efficiencies are strongly hampered by anomalously large voltage loss (>0.6 V), whose origin remains controversial so far. Herein, by combining ultrafast pump-probe spectroscopy and density functional theory (DFT) calculation, the coupled electronic and structural dynamics leading to excited state self-trapping in antimony chalcogenides with atomic level characterizations is reported. The electronic dynamics in Sb2 Se3 indicates a ≈20 ps barrierless intrinsic self-trapping, with electron localization and accompanied lattice distortion given by DFT calculations. Furthermore, impulsive vibrational coherences unveil key SbSe vibrational modes and their real-time interplay that drive initial excited state relaxation and energy dissipation toward stabilized small polaron through electron-phonon and subsequent phonon-phonon coupling. This study's findings provide conclusive evidence of carrier self-trapping arising from intrinsic lattice anharmonicity and polaronic effect in antimony chalcogenides and a new understanding on the coupled electronic and structural dynamics for redefining excited state properties in soft semiconductor materials.
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Affiliation(s)
- Weijian Tao
- State Key Laboratory of Modern Optical InstrumentationKey Laboratory of Excited‐State Materials of Zhejiang ProvinceDepartment of ChemistryZhejiang UniversityHangzhouZhejiang310027China
| | - Leilei Zhu
- State Key Laboratory of Computer ArchitectureInstitute of Computing TechnologyChinese Academy of SciencesBeijing100190China
| | - Kanghua Li
- Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic InformationHuazhong University of Science and TechnologyHubei430074China
| | - Chao Chen
- Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic InformationHuazhong University of Science and TechnologyHubei430074China
| | - Yuzhong Chen
- State Key Laboratory of Modern Optical InstrumentationKey Laboratory of Excited‐State Materials of Zhejiang ProvinceDepartment of ChemistryZhejiang UniversityHangzhouZhejiang310027China
| | - Yujie Li
- State Key Laboratory of Modern Optical InstrumentationKey Laboratory of Excited‐State Materials of Zhejiang ProvinceDepartment of ChemistryZhejiang UniversityHangzhouZhejiang310027China
| | - Xufeng Li
- State Key Laboratory of Modern Optical InstrumentationKey Laboratory of Excited‐State Materials of Zhejiang ProvinceDepartment of ChemistryZhejiang UniversityHangzhouZhejiang310027China
| | - Jiang Tang
- Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic InformationHuazhong University of Science and TechnologyHubei430074China
| | - Honghui Shang
- State Key Laboratory of Computer ArchitectureInstitute of Computing TechnologyChinese Academy of SciencesBeijing100190China
| | - Haiming Zhu
- State Key Laboratory of Modern Optical InstrumentationKey Laboratory of Excited‐State Materials of Zhejiang ProvinceDepartment of ChemistryZhejiang UniversityHangzhouZhejiang310027China
- Zhejiang University‐Hangzhou Global Scientific and Technological Innovation CenterHangzhou310014China
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27
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Hong Y, Schlosser F, Kim W, Würthner F, Kim D. Ultrafast Symmetry-Breaking Charge Separation in a Perylene Bisimide Dimer Enabled by Vibronic Coupling and Breakdown of Adiabaticity. J Am Chem Soc 2022; 144:15539-15548. [PMID: 35951363 DOI: 10.1021/jacs.2c03916] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Perylene bisimides (PBIs) have received great attention in their applicability to optoelectronics. Especially, symmetry-breaking charge separation (SB-CS) in PBIs has been investigated to mimic the efficient light capturing and charge generation in natural light-harvesting systems. However, unlike ultrafast CS dynamics in donor-acceptor heterojunction materials, ultrafast SB-CS in a stacked homodimer has still been challenging due to excimer formation in the absence of rigidifying surroundings such as a special pair in the natural systems. Herein, we present the detailed mechanism of ultrafast photoinduced SB-CS occurring in a 1,7-bis(N-pyrrolidinyl) PBI dimer within a cyclophane. Through narrow-band and broad-band transient absorption spectroscopy, we demonstrate that ultrafast SB-CS in the dimer is enabled by the combination of (1) vibrationally coherent charge-transfer resonance-enhanced excimer formation and (2) breakdown of adiabaticity (formation of SB-CS diabats) in the excimer state via structural and solvent fluctuation. Quantum chemical calculations also underpin that the participation of strong electron-donating substituents in overall vibrational modes plays a crucial role in triggering the ultrafast SB-CS. Therefore, our work provides an alternative route to facilitate ultrafast SB-CS in PBIs and thereby establishes a novel strategy for the design of optoelectronic materials.
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Affiliation(s)
- Yongseok Hong
- Department of Chemistry, Yonsei University, Seoul 03722, Korea
| | - Felix Schlosser
- Institut für Organische Chemie & Center for Nanosystems Chemistry, Universitat Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Woojae Kim
- Department of Chemistry, Yonsei University, Seoul 03722, Korea
| | - Frank Würthner
- Institut für Organische Chemie & Center for Nanosystems Chemistry, Universitat Würzburg, Am Hubland, Würzburg 97074, Germany
| | - Dongho Kim
- Department of Chemistry, Yonsei University, Seoul 03722, Korea.,Division of Energy Materials, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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28
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Mitra S, Ainavarapu SRK, Dasgupta J. Long-Range Charge Delocalization Mediates the Ultrafast Ligand-to-Metal Charge Transfer Dynamics at the Cu 2+-Active Site in Azurin. J Phys Chem B 2022; 126:5390-5399. [PMID: 35797135 DOI: 10.1021/acs.jpcb.2c01427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The blue color metalloprotein in azurin has traditionally been attributed to the intense cysteine-to-Cu2+ ligand-to-metal charge transfer transition centered at 628 nm. Although resonance Raman measurements of the Cu2+ active site have implied that the LMCT transition electronically couples to the protein scaffold well beyond its primary metal-ligand coordination shell, the structural extent of this electronic coupling and visualization of the protein-mediated charge transfer dynamics have remained elusive. Here, using femtosecond broadband transient absorption and impulsive Raman spectroscopy, we provide direct evidence for a rapid relaxation between two distinct charge transfer states, having different spatial delocalization, within ∼300 fs followed by recombination of charges in subpicosecond time scales. We invoke the formation of a protein-centered radical cation, possibly Trp48 or a Phe residue, within 100 fs substantiating the long-range electronic coupling for the first time beyond the traditional copper active site. The Raman spectra of the excited CT state show the presence of protein-centric vibrations along with the vibrational modes assigned to the copper active site. Our results demonstrate a large delocalization length scale of the initially populated CT state, thereby highlighting the possibility of exploiting azurin photochemistry for energy conversion techniques.
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Affiliation(s)
- Soumyajit Mitra
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
| | | | - Jyotishman Dasgupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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29
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Barclay M, Huff JS, Pensack RD, Davis PH, Knowlton WB, Yurke B, Dean JC, Arpin PC, Turner DB. Characterizing Mode Anharmonicity and Huang-Rhys Factors Using Models of Femtosecond Coherence Spectra. J Phys Chem Lett 2022; 13:5413-5423. [PMID: 35679146 PMCID: PMC9234982 DOI: 10.1021/acs.jpclett.1c04162] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 06/06/2022] [Indexed: 06/15/2023]
Abstract
Femtosecond laser pulses readily produce coherent quantum beats in transient-absorption spectra. These oscillatory signals often arise from molecular vibrations and therefore may contain information about the excited-state potential energy surface near the Franck-Condon region. Here, by fitting the measured spectra of two laser dyes to microscopic models of femtosecond coherence spectra (FCS) arising from molecular vibrations, we classify coherent quantum-beat signals as fundamentals or overtones and quantify their Huang-Rhys factors and anharmonicity values. We discuss the extracted Huang-Rhys factors in the context of quantum-chemical computations. This work solidifies the use of FCS for analysis of coherent quantum beats arising from molecular vibrations, which will aid studies of molecular aggregates and photosynthetic proteins.
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Affiliation(s)
- Matthew
S. Barclay
- Micron
School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Jonathan S. Huff
- Micron
School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Ryan D. Pensack
- Micron
School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Paul H. Davis
- Micron
School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
| | - William B. Knowlton
- Micron
School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
- Department
of Electrical & Computer Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Bernard Yurke
- Micron
School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
- Department
of Electrical & Computer Engineering, Boise State University, Boise, Idaho 83725, United States
| | - Jacob C. Dean
- Department
of Physical Science, Southern Utah University, Cedar City, Utah 84720, United States
| | - Paul C. Arpin
- Department
of Physics, California State University,
Chico, Chico, California 95929, United States
| | - Daniel B. Turner
- Micron
School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
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30
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Dhamija S, Bhutani G, Jayachandran A, De AK. A Revisit on Impulsive Stimulated Raman Spectroscopy: Importance of Spectral Dispersion of Chirped Broadband Probe. J Phys Chem A 2022; 126:1019-1032. [PMID: 35142494 DOI: 10.1021/acs.jpca.1c10566] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The usefulness of a chirped broadband probe and spectral dispersion to obtain Raman spectra under nonresonant/resonant impulsive excitation is revisited. A general methodology is presented that inherently takes care of phasing the time-domain low-frequency oscillations without probe pulse compression and retrieves the absolute phase of the oscillations. As test beds, neat solvents (CCl4, CHCl3, and CH2Cl2) are used. Observation of periodic intensity modulation along detection wavelengths for particular modes is explained using a simple electric field interaction picture. This method is extended to diatomic molecule (iodine) and polyatomic molecules (Nile blue and methylene blue) to assign vibrational frequencies in ground/excited electronic state that are supported by density functional theory calculations. A comparison between frequency-domain and time-domain counterparts, i.e., stimulated Raman scattering and impulsive stimulated Raman scattering using degenerate pump-probe pairs is presented, and most importantly, it is shown how impulsive stimulated Raman scattering using chirped broadband probe retains unique advantages offered by both.
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Affiliation(s)
- Shaina Dhamija
- Condensed Phase Dynamics Group, Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Garima Bhutani
- Condensed Phase Dynamics Group, Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Ajay Jayachandran
- Condensed Phase Dynamics Group, Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
| | - Arijit K De
- Condensed Phase Dynamics Group, Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab 140306, India
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31
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Bressan G, Jirasek M, Roy P, Anderson HL, Meech SR, Heisler IA. Population and Coherence Dynamics in Large Conjugated Porphyrin Nanorings. Chem Sci 2022; 13:9624-9636. [PMID: 36091893 PMCID: PMC9400675 DOI: 10.1039/d2sc01971j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/12/2022] [Indexed: 11/28/2022] Open
Abstract
In photosynthesis, nature exploits the distinctive electronic properties of chromophores arranged in supramolecular rings for efficient light harvesting. Among synthetic supramolecular cyclic structures, porphyrin nanorings have attracted considerable attention as they have a resemblance to naturally occurring light-harvesting structures but offer the ability to control ring size and the level of disorder. Here, broadband femtosecond transient absorption spectroscopy, with pump pulses in resonance with either the high or the low energy sides of the inhomogeneously broadened absorption spectrum, is used to study the population dynamics and ground and excited state vibrational coherence in large porphyrin nanorings. A series of fully conjugated, alkyne bridged, nanorings constituted of between ten and forty porphyrin units is studied. Pump-wavelength dependent fast spectral evolution is found. A fast rise or decay of the stimulated emission is found when large porphyrin nanorings are excited on, respectively, the high or low energy side of the absorption spectrum. Such dynamics are consistent with the hypothesis of a variation in transition dipole moment across the inhomogeneously broadened ground state ensemble. The observed dynamics indicate the interplay of nanoring conformation and oscillator strength. Oscillatory dynamics on the sub-ps time domain are observed in both pumping conditions. A combined analysis of the excitation wavelength-dependent transient spectra along with the amplitude and phase evolution of the oscillations allows assignment to vibrational wavepackets evolving on either ground or excited states electronic potential energy surfaces. Even though porphyrin nanorings support highly delocalized electronic wavefunctions, with coherence length spanning tens of chromophores, the measured vibrational coherences remain localised on the monomers. The main contributions to the beatings are assigned to two vibrational modes localised on the porphyrin cores: a Zn–N stretching mode and a skeletal methinic/pyrrolic C–C stretching and in-plane bending mode. Pump wavelength-dependent, ultrafast excited state dynamics arising from inhomogeneous broadening and ground and excited state nuclear wavepackets were observed for a series of Zn porphyrin nanorings made of 10 to 40 repeating units.![]()
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Affiliation(s)
- Giovanni Bressan
- School of Chemistry Norwich Research Park, University of East Anglia Norwich NR4 7TJ UK
| | - Michael Jirasek
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory Oxford OX1 3TA UK
| | - Palas Roy
- School of Chemistry Norwich Research Park, University of East Anglia Norwich NR4 7TJ UK
| | - Harry L Anderson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory Oxford OX1 3TA UK
| | - Stephen R Meech
- School of Chemistry Norwich Research Park, University of East Anglia Norwich NR4 7TJ UK
| | - Ismael A Heisler
- Instituto de Física, Universidade Federal do Rio Grande do Sul Avenida Bento Gonçalves, 9500, CEP 91501-970 Porto Alegre Brazil
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32
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Tang L, Fang C. Fluorescence Modulation by Ultrafast Chromophore Twisting Events: Developing a Powerful Toolset for Fluorescent-Protein-Based Imaging. J Phys Chem B 2021; 125:13610-13623. [PMID: 34883016 DOI: 10.1021/acs.jpcb.1c08570] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The advancement of modern life sciences has benefited tremendously from the discovery and development of fluorescent proteins (FPs), widely expressed in live cells to track a myriad of cellular events. The chromophores of various FPs can undergo many ultrafast photophysical and/or photochemical processes in the electronic excited state and emit fluorescence with different colors. However, the chromophore becomes essentially nonfluorescent in solution environment due to its intrinsic twisting capability upon photoexcitation. To study "microscopic" torsional events and their effects on "macroscopic" fluorescence, we have developed an integrated ultrafast characterization platform involving femtosecond transient absorption (fs-TA) and wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS). A wide range of naturally occurring, circularly permuted, non-canonical amino-acid-decorated FPs and FP-based optical highlighters with photochromicity, photoconversion, and/or photoswitching capabilities have been recently investigated in great detail. Twisting conformational motions were elucidated to exist in all of these systems but to various extents. The associated different ultrafast pathways can be monitored via frequency changes of characteristic Raman bands during primary events and functional processes. The mapped electronic and structural dynamics information is crucial and has shown great potential and initial success for the rational design of proteins and other photoreceptors with novel functions and fluorescence properties.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, United States
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33
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Keil E, Malevich P, Hauer J. Achromatic frequency doubling of supercontinuum pulses for transient absorption spectroscopy. OPTICS EXPRESS 2021; 29:39042-39054. [PMID: 34809275 DOI: 10.1364/oe.442400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
We present achromatic frequency doubling of supercontinuum pulses from a hollow core fiber as a technique for obtaining tunable ultrashort pulses in the near UV and blue spectral range. Pulse energies are stable on a 1.1% level, averaged over 100 000 shots. By the use of conventional optics only, we compress a 0.2 µJ pulse at a center wavelength of 475 nm to a pulse duration of 12 fs, as measured by X-FROG. We test the capabilities of the approach by employing the ASHG-pulses as a pump in a transient absorption experiment on β-carotene in solution.
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34
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Batignani G, Sansone C, Ferrante C, Fumero G, Mukamel S, Scopigno T. Excited-State Energy Surfaces in Molecules Revealed by Impulsive Stimulated Raman Excitation Profiles. J Phys Chem Lett 2021; 12:9239-9247. [PMID: 34533307 PMCID: PMC8488957 DOI: 10.1021/acs.jpclett.1c02209] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/16/2021] [Indexed: 05/14/2023]
Abstract
Photophysical and photochemical processes are ruled by the interplay between transient vibrational and electronic degrees of freedom, which are ultimately determined by the multidimensional potential energy surfaces (PESs). Differences between ground and excited PESs are encoded in the relative intensities of resonant Raman bands, but they are experimentally challenging to access, requiring measurements at multiple wavelengths under identical conditions. Herein, we perform a two-color impulsive vibrational scattering experiment to launch nuclear wavepacket motions by an impulsive pump and record their coupling with a targeted excited-state potential by resonant Raman processes with a delayed probe, generating in a single measurement background-free vibrational spectra across the entire sample absorption. Building on the interference between the multiple pathways resonant with the excited-state manifold that generate the Raman signal, we show how to experimentally tune their relative phase by varying the probe chirp, decoding nuclear displacements along different normal modes and revealing the multidimensional PESs. Our results are validated against time-dependent density functional theory.
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Affiliation(s)
- Giovanni Batignani
- Dipartimento
di Fisica, Universitá di Roma “La
Sapienza”, Roma I-00185, Italy
- Istituto
Italiano di Tecnologia, Center for Life Nano Science @Sapienza, Roma I-00161, Italy
| | - Carlotta Sansone
- Dipartimento
di Fisica, Universitá di Roma “La
Sapienza”, Roma I-00185, Italy
| | - Carino Ferrante
- Dipartimento
di Fisica, Universitá di Roma “La
Sapienza”, Roma I-00185, Italy
- Istituto
Italiano di Tecnologia, Center for Life Nano Science @Sapienza, Roma I-00161, Italy
| | - Giuseppe Fumero
- Dipartimento
di Fisica, Universitá di Roma “La
Sapienza”, Roma I-00185, Italy
| | - Shaul Mukamel
- Department
of Chemistry, University of California, Irvine, California 92623, United States
| | - Tullio Scopigno
- Dipartimento
di Fisica, Universitá di Roma “La
Sapienza”, Roma I-00185, Italy
- Istituto
Italiano di Tecnologia, Center for Life Nano Science @Sapienza, Roma I-00161, Italy
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35
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van Stokkum IHM, Kloz M, Polli D, Viola D, Weißenborn J, Peerbooms E, Cerullo G, Kennis JTM. Vibronic dynamics resolved by global and target analysis of ultrafast transient absorption spectra. J Chem Phys 2021; 155:114113. [PMID: 34551543 DOI: 10.1063/5.0060672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a methodology that provides a complete parametric description of the time evolution of the electronically and vibrationally excited states as detected by ultrafast transient absorption (TA). Differently from previous approaches, which started fitting the data after ≈100 fs, no data are left out in our methodology, and the "coherent artifact" and the instrument response function are fully taken into account. In case studies, the method is applied to solvents, the dye Nile blue, and all-trans β-carotene in cyclohexane solution. The estimated Damped Oscillation Associated Spectra (DOAS) and phases express the most important vibrational frequencies present in the molecular system. By global fit alone of the experimental data, it is difficult to interpret in detail the underlying dynamics. Since it is unfeasible to directly fit the data by a theoretical simulation, our enhanced DOAS methodology thus provides a useful "middle ground" where the theoretical description and the fit of the experimental data can meet. β-carotene in cyclohexane was complementarily studied with femtosecond stimulated Raman spectroscopy (FSRS). The fs-ps dynamics of β-carotene in cyclohexane in TA and FSRS experiments can be described by a sequential scheme S2 → hot S1 → S1' → S1 → S0 with lifetimes of 167 fs (fixed), 0.35, 1.1, and 9.6 ps. The correspondence of DOAS decaying concomitantly with hot S1 and the Species Associated Difference Spectra of hot S1 in TA and FSRS suggest that we observe here features of the vibrational relaxation and nuclear reorganization responsible for the hot S1 to S1 transition.
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Affiliation(s)
- Ivo H M van Stokkum
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Miroslav Kloz
- Institute of Physics, ELI Beamlines, Academy of Sciences of the Czech Republic, CZ-18221 Prague, Czech Republic
| | - Dario Polli
- IFN-CNR, Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Daniele Viola
- IFN-CNR, Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Jörn Weißenborn
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Ebo Peerbooms
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Giulio Cerullo
- IFN-CNR, Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - John T M Kennis
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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36
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Mewes L, Ingle RA, Al Haddad A, Chergui M. Broadband visible two-dimensional spectroscopy of molecular dyes. J Chem Phys 2021; 155:034201. [PMID: 34293898 DOI: 10.1063/5.0053554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Two-dimensional Fourier transform spectroscopy is a promising technique to study ultrafast molecular dynamics. Similar to transient absorption spectroscopy, a more complete picture of the dynamics requires broadband laser pulses to observe transient changes over a large enough bandwidth, exceeding the inhomogeneous width of electronic transitions, as well as the separation between the electronic or vibronic transitions of interest. Here, we present visible broadband 2D spectra of a series of dye molecules and report vibrational coherences with frequencies up to ∼1400 cm-1 that were obtained after improvements to our existing two-dimensional Fourier transform setup [Al Haddad et al., Opt. Lett. 40, 312-315 (2015)]. The experiment uses white light from a hollow core fiber, allowing us to acquire 2D spectra with a bandwidth of 200 nm, in a range between 500 and 800 nm, and with a temporal resolution of 10-15 fs. 2D spectra of nile blue, rhodamine 800, terylene diimide, and pinacyanol iodide show vibronic spectral features with at least one vibrational mode and reveal information about structural motion via coherent oscillations of the 2D signals during the population time. For the case of pinacyanol iodide, these observations are complemented by its Raman spectrum, as well as the calculated Raman activity at the ground- and excited-state geometry.
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Affiliation(s)
- Lars Mewes
- Laboratoire de Spectroscopie Ultrarapide and LACUS, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB-BSP, CH-1015 Lausanne, Switzerland
| | - Rebecca A Ingle
- Laboratoire de Spectroscopie Ultrarapide and LACUS, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB-BSP, CH-1015 Lausanne, Switzerland
| | - Andre Al Haddad
- Laboratoire de Spectroscopie Ultrarapide and LACUS, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB-BSP, CH-1015 Lausanne, Switzerland
| | - Majed Chergui
- Laboratoire de Spectroscopie Ultrarapide and LACUS, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB-BSP, CH-1015 Lausanne, Switzerland
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37
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Coherent vibrational dynamics reveals lattice anharmonicity in organic-inorganic halide perovskite nanocrystals. Nat Commun 2021; 12:2629. [PMID: 33976185 PMCID: PMC8113605 DOI: 10.1038/s41467-021-22934-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 03/30/2021] [Indexed: 12/05/2022] Open
Abstract
The halide ions of organic-inorganic hybrid perovskites can strongly influence the interaction between the central organic moiety and the inorganic metal halide octahedral units and thus their lattice vibrations. Here, we report the halide-ion-dependent vibrational coherences in formamidinium lead halide (FAPbX3, X = Br, I) perovskite nanocrystals (PNCs) via the combination of femtosecond pump–probe spectroscopy and density functional theory calculations. We find that the FAPbX3 PNCs generate halide-dependent coherent vibronic wave packets upon above-bandgap non-resonant excitation. More importantly, we observe several higher harmonics of the fundamental modes for FAPbI3 PNCs as compared to FAPbBr3 PNCs. This is likely due to the weaker interaction between the central FA moiety and the inorganic cage for FAPbI3 PNCs, and thus the PbI64− unit can vibrate more freely. This weakening reveals the intrinsic anharmonicity in the Pb-I framework, and thus facilitating the energy transfer into overtone and combination bands. These findings not only unveil the superior stability of Br–based PNCs over I–based PNCs but are also important for a better understanding of their electronic and polaronic properties. Using a combination of femtosecond pump-probe spectroscopy and first-principles calculations, Debnath et al. elucidated the halide-dependence of the excited state vibrational coherences in hybrid organic-inorganic perovskite nanocrystals. The study revealed an intrinsic anharmonicity of lead-halide framework, which correlates with perovskite stability and is influenced by the interaction between the framework and the organic molecules.
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38
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Arpin PC, Turner DB. Signatures of Vibrational and Electronic Quantum Beats in Femtosecond Coherence Spectra. J Phys Chem A 2021; 125:2425-2435. [PMID: 33724844 PMCID: PMC8023717 DOI: 10.1021/acs.jpca.0c10807] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Indexed: 11/29/2022]
Abstract
Femtosecond laser pulses can produce oscillatory signals in transient-absorption spectroscopy measurements. The quantum beats are often studied using femtosecond coherence spectra (FCS), the Fourier domain amplitude, and phase profiles at individual oscillation frequencies. In principle, one can identify the mechanism that gives rise to each quantum-beat signal by comparing its measured FCS to those arising from microscopic models. To date, however, most measured FCS deviate from the ubiquitous harmonic oscillator model. Here, we expand the inventory of models to which the measured spectra can be compared. We develop quantum-mechanical models of the fundamental, overtone, and combination-band FCS arising from harmonic potentials, the FCS of anharmonic potentials, and the FCS of a purely electronic dimer. This work solidifies the use of FCS for identifying electronic coherences that can arise in measurements of molecular aggregates including photosynthetic proteins. Furthermore, future studies can use the derived expressions to fit the measured FCS and thereby extract microscopic parameters of molecular potential-energy surfaces.
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Affiliation(s)
- Paul C. Arpin
- Department
of Physics, California State University,
Chico, Chico, California 95929, United States
| | - Daniel B. Turner
- Micron
School for Materials Science and Engineering, Boise State University, Boise, Idaho 83725, United States
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39
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Krueger TD, Giesbers G, Van Court RC, Zhu L, Kim R, Beaudry CM, Robinson SC, Ostroverkhova O, Fang C. Ultrafast Dynamics and Photoresponse of a Fungi-Derived Pigment Xylindein from Solution to Thin Films. Chemistry 2021; 27:5627-5631. [PMID: 33543812 DOI: 10.1021/acs.jpcc.0c09627] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/05/2021] [Indexed: 05/22/2023]
Abstract
Organic semiconductor materials have recently gained momentum due to their non-toxicity, low cost, and sustainability. Xylindein is a remarkably photostable pigment secreted by fungi that grow on decaying wood, and its relatively strong electronic performance is enabled by π-π stacking and hydrogen-bonding network that promote charge transport. Herein, femtosecond transient absorption spectroscopy with a near-IR probe was used to unveil a rapid excited-state intramolecular proton transfer reaction. Conformational motions potentially lead to a conical intersection that quenches fluorescence in the monomeric state. In concentrated solutions, nascent aggregates exhibit a faster excited state lifetime due to excimer formation, confirmed by the excimer→charge-transfer excited-state absorption band of the xylindein thin film, thus limiting its optoelectronic performance. Therefore, extending the xylindein sidechains with branched alkyl groups may hinder the excimer formation and improve optoelectronic properties of naturally derived materials.
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Affiliation(s)
- Taylor D Krueger
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR, 97331-4003, USA
| | - Gregory Giesbers
- Department of Physics, Oregon State University, 301 Weniger Hall, Corvallis, OR, 97331-6507, USA
| | - Ray C Van Court
- Department of Wood Science and Engineering, Oregon State University, 119 Richardson Hall, Corvallis, OR, 97331-5704, USA
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR, 97331-4003, USA
| | - Ryan Kim
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR, 97331-4003, USA
| | - Christopher M Beaudry
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR, 97331-4003, USA
| | - Seri C Robinson
- Department of Wood Science and Engineering, Oregon State University, 119 Richardson Hall, Corvallis, OR, 97331-5704, USA
| | - Oksana Ostroverkhova
- Department of Physics, Oregon State University, 301 Weniger Hall, Corvallis, OR, 97331-6507, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR, 97331-4003, USA
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40
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Wan Y, Chang W. Effect of decreasing pressure on soliton self-compression in higher-order modes of a gas-filled capillary. OPTICS EXPRESS 2021; 29:7070-7083. [PMID: 33726215 DOI: 10.1364/oe.418217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 02/14/2021] [Indexed: 06/12/2023]
Abstract
We numerically investigate soliton self-compression in the higher-order modes of a gas-filled capillary with decreasing pressure. We demonstrate four times enhancement in the compression with the decreasing pressure compared to the equivalent constant pressure case in the HE12 mode, reaching sub-cycle duration of 1.85 fs at its output. Moreover, the negative pressure gradient effectively suppresses the intermodal coupling in the later stage of the compressor, which helps to maintain high output mode purity. These findings are of direct benefit for applications that require ultrashort light pulses in unconventional spatial beam profiles, including in nonlinear frequency conversion, microscopy, micromachining, and particle manipulation.
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41
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Acharyya N, Ovcharenko R, Fingerhut BP. On the role of non-diagonal system-environment interactions in bridge-mediated electron transfer. J Chem Phys 2020; 153:185101. [PMID: 33187441 DOI: 10.1063/5.0027976] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Bridge-mediated electron transfer (ET) between a donor and an acceptor is prototypical for the description of numerous most important ET scenarios. While multi-step ET and the interplay of sequential and direct superexchange transfer pathways in the donor-bridge-acceptor (D-B-A) model are increasingly understood, the influence of off-diagonal system-bath interactions on the transfer dynamics is less explored. Off-diagonal interactions account for the dependence of the ET coupling elements on nuclear coordinates (non-Condon effects) and are typically neglected. Here, we numerically investigate with quasi-adiabatic propagator path integral simulations the impact of off-diagonal system-environment interactions on the transfer dynamics for a wide range of scenarios in the D-B-A model. We demonstrate that off-diagonal system-environment interactions can have profound impact on the bridge-mediated ET dynamics. In the considered scenarios, the dynamics itself does not allow for a rigorous assignment of the underlying transfer mechanism. Furthermore, we demonstrate how off-diagonal system-environment interaction mediates anomalous localization by preventing long-time depopulation of the bridge B and how coherent transfer dynamics between donor D and acceptor A can be facilitated. The arising non-exponential short-time dynamics and coherent oscillations are interpreted within an equivalent Hamiltonian representation of a primary reaction coordinate model that reveals how the complex vibronic interplay of vibrational and electronic degrees of freedom underlying the non-Condon effects can impose donor-to-acceptor coherence transfer on short timescales.
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Affiliation(s)
- Nirmalendu Acharyya
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
| | - Roman Ovcharenko
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
| | - Benjamin P Fingerhut
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
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42
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Ron A, Chaudhary S, Zhang G, Ning H, Zoghlin E, Wilson SD, Averitt RD, Refael G, Hsieh D. Ultrafast Enhancement of Ferromagnetic Spin Exchange Induced by Ligand-to-Metal Charge Transfer. PHYSICAL REVIEW LETTERS 2020; 125:197203. [PMID: 33216570 DOI: 10.1103/physrevlett.125.197203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 08/17/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
We theoretically predict and experimentally demonstrate a nonthermal pathway to optically enhance superexchange interaction energies in a material based on exciting ligand-to-metal charge-transfer transitions, which introduces lower-order virtual hopping contributions that are absent in the ground state. We demonstrate this effect in the layered ferromagnetic insulator CrSiTe_{3} by exciting Te-to-Cr charge-transfer transitions using ultrashort laser pulses and detecting coherent phonon oscillations that are impulsively generated by superexchange enhancement via magneto-elastic coupling. This mechanism kicks in below the temperature scale where short-range in-plane spin correlations begin to develop and disappears when the excitation energy is tuned away from the charge-transfer resonance, consistent with our predictions.
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Affiliation(s)
- A Ron
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel Aviv, 69978, Israel
| | - S Chaudhary
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - G Zhang
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
| | - H Ning
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - E Zoghlin
- Materials Department, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - S D Wilson
- Materials Department, University of California, Santa Barbara, Santa Barbara, California 93106, USA
| | - R D Averitt
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
| | - G Refael
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
| | - D Hsieh
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
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44
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Ko YK, Yabushita A, Kobayashi T. Primary Electronic and Vibrational Dynamics of Cytochrome c Observed by Sub-10 fs NUV Laser Pulses. J Phys Chem B 2020; 124:8249-8258. [PMID: 32852960 DOI: 10.1021/acs.jpcb.0c05959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The primary reaction mechanism of cytochrome c (Cyt c) was elucidated for two redox forms of ferric (oxidized) and ferrous (reduced) Cyt c by measuring their transient absorption (TA) spectra using a homemade sub-10 fs broadband NUV laser pulses system. The TA traces measured in the broad probe wavelength region were analyzed by the global analysis method to study the electronic dynamics. The difference of relaxation dynamics dependent on the excitation bandwidth enabled us to elucidate that the 2.5 ps component in ferrous Cyt c can be assigned to intramolecular vibration energy redistribution and not to vibrational cooling, which was not clear until this work. The temporal resolution of 10 fs observes TA signal modulation caused by the molecular vibration in the time domain, which can be used to calculate the instantaneous frequency of the molecular vibration mode. The observed vibrational dynamics has visualized that the heme structure changes in 0.8 ps for ferric Cyt c and in >1.0 ps for ferrous Cyt c. These estimated lifetimes of vibrational dynamics reflect vibrational relaxation in the ground state of ferric Cyt c and electronic transition from the S2 state to the S1 state in ferrous Cyt c, respectively.
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Affiliation(s)
- Ying Kuan Ko
- Department of Electrophysics, National Chiao-Tung University, Hsinchu 300, Taiwan, R.O.C
| | - Atsushi Yabushita
- Department of Electrophysics, National Chiao-Tung University, Hsinchu 300, Taiwan, R.O.C
| | - Takayoshi Kobayashi
- Department of Electrophysics, National Chiao-Tung University, Hsinchu 300, Taiwan, R.O.C
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45
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Rich CC, Frontiera RR. Uncovering the Functional Role of Coherent Phonons during the Photoinduced Phase Transition in a Molecular Crystal. J Phys Chem Lett 2020; 11:7502-7509. [PMID: 32845635 DOI: 10.1021/acs.jpclett.0c01834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The atomic motions that make up phonons and molecular vibrations in molecular crystals influence their photophysical and electronic properties, including polaron formation, carrier mobility, and phase transitions. Discriminating between spectator and driving motions is a significant challenge hindering optimization. Unlocking this information and developing fine-tuned controls over actively participating phonon modes would not only lead to a stronger understanding of photochemistry but also provide a significant new tool in controlling solid state chemistry. We present a strategy using rationally designed double pulses to unveil the unique function of specific excited state phonon modes. Using ultrafast spectroscopy, we identified 50 and 90 cm-1 phonons involved in modulating the photoinduced spin-Peierls melting of potassium tetracyanoquinodimethane crystals. We show that the 50 cm-1 phonon specifically corresponds to the coherent nuclear wavepacket involved in the charge transfer component of the overall spin-Peierls phase melting process, while the 90 cm-1 phonon facilitates the phase transition component.
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Affiliation(s)
- Christopher C Rich
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Renee R Frontiera
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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46
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Fitzpatrick C, Odhner JH, Levis RJ. Spectral Signatures of Ground- and Excited-State Wavepacket Interference after Impulsive Excitation. J Phys Chem A 2020; 124:6856-6866. [PMID: 32786657 DOI: 10.1021/acs.jpca.0c03912] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Impulsive transient absorption spectroscopy is used to track the formation and evolution of vibrational coherences in cresyl violet perchlorate under different excitation conditions. Resonant and off-resonant pump pulses result in the selective formation of excited (S1)- and ground (S0)-state wavepackets. Partially resonant and broadband excitation conditions lead to the simultaneous formation of wavepackets in the ground and excited states. The wavepackets are characterized by the phase-flips in the coherent signal associated with wavepacket motion across the absorption and emission maxima and by a red shift of 2-10 cm-1 in the Raman features of the excited state compared to the ground-state wavepacket. We observe that, when wavepackets are simultaneously excited on the ground- and excited-state surfaces, interference on a picosecond timescale between coherent oscillations in the two wavepackets gives rise to features that cannot be attributed to the passage of a wavepacket through a conical intersection, such as shifting phase-flips and zero-amplitude nodes. Wavepacket filtering using windowed Fourier transforms highlights these interference effects and demonstrates that special care must be taken in order to properly interpret data that have been processed in this manner.
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Affiliation(s)
- Colin Fitzpatrick
- Center for Advanced Photonics Research, Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Johanan H Odhner
- Center for Advanced Photonics Research, Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, Pennsylvania 19122, United States
| | - Robert J Levis
- Center for Advanced Photonics Research, Department of Chemistry, Temple University, 1901 N. 13th Street, Philadelphia, Pennsylvania 19122, United States
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47
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Van Stappen C, Decamps L, Cutsail GE, Bjornsson R, Henthorn JT, Birrell JA, DeBeer S. The Spectroscopy of Nitrogenases. Chem Rev 2020; 120:5005-5081. [PMID: 32237739 PMCID: PMC7318057 DOI: 10.1021/acs.chemrev.9b00650] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Indexed: 01/08/2023]
Abstract
Nitrogenases are responsible for biological nitrogen fixation, a crucial step in the biogeochemical nitrogen cycle. These enzymes utilize a two-component protein system and a series of iron-sulfur clusters to perform this reaction, culminating at the FeMco active site (M = Mo, V, Fe), which is capable of binding and reducing N2 to 2NH3. In this review, we summarize how different spectroscopic approaches have shed light on various aspects of these enzymes, including their structure, mechanism, alternative reactivity, and maturation. Synthetic model chemistry and theory have also played significant roles in developing our present understanding of these systems and are discussed in the context of their contributions to interpreting the nature of nitrogenases. Despite years of significant progress, there is still much to be learned from these enzymes through spectroscopic means, and we highlight where further spectroscopic investigations are needed.
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Affiliation(s)
- Casey Van Stappen
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Laure Decamps
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - George E. Cutsail
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Ragnar Bjornsson
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Justin T. Henthorn
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - James A. Birrell
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max Planck Institute for
Chemical Energy Conversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
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48
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Jiang X, Jun S, Hoffman J, Kanatzidis MG, Harel E. Global Analysis for Time and Spectrally Resolved Multidimensional Microscopy: Application to CH 3NH 3PbI 3 Perovskite Thin Films. J Phys Chem A 2020; 124:4837-4847. [PMID: 32421331 DOI: 10.1021/acs.jpca.0c01829] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The advancement of improved photoactive materials, such as those proposed for next-generation solar cells, low-power lighting, and lasing applications, requires a deep understanding of their correlated spatial, spectral, and temporal properties. In principle, correlated time-resolved microscopy techniques are capable of capturing such information. However, the large data sets that encapsulate temporal, spectral, and spatial information create the prodigious challenge of analyzing gigabytes of correlated data, which typically takes enormous computational resources. These challenges motivate the development of robust and efficient data analysis tools to realize fast spatial and spectral decomposition and to gain physical insights that arise from statistical analysis. Herein, we propose a reliable and fast global analysis method based on variable projection and subsampling methods, which exhibits exceptionally high sensitivity to buried spatial and spectral information in large and multidimensional microscopy data sets as compared to traditional methods. The reliability and robustness of this new method is tested on transient absorption and impulsive vibrational microscopy data sets acquired on polycrystalline CH3NH3PbI3 perovskite films.
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Affiliation(s)
- Xinyi Jiang
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Sunhong Jun
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Justin Hoffman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Mercouri G Kanatzidis
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Elad Harel
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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49
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Kim W, Kim T, Kang S, Hong Y, Würthner F, Kim D. Tracking Structural Evolution during Symmetry‐Breaking Charge Separation in Quadrupolar Perylene Bisimide with Time‐Resolved Impulsive Stimulated Raman Spectroscopy. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202002733] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Woojae Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
| | - Taeyeon Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
| | - Seongsoo Kang
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
| | - Yongseok Hong
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
| | - Frank Würthner
- Institut für Organische Chemie & Center for, Nanosystems Chemistry Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Dongho Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
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50
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Kim W, Kim T, Kang S, Hong Y, Würthner F, Kim D. Tracking Structural Evolution during Symmetry‐Breaking Charge Separation in Quadrupolar Perylene Bisimide with Time‐Resolved Impulsive Stimulated Raman Spectroscopy. Angew Chem Int Ed Engl 2020; 59:8571-8578. [DOI: 10.1002/anie.202002733] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Indexed: 01/12/2023]
Affiliation(s)
- Woojae Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
| | - Taeyeon Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
| | - Seongsoo Kang
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
| | - Yongseok Hong
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
| | - Frank Würthner
- Institut für Organische Chemie & Center for, Nanosystems Chemistry Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Dongho Kim
- Department of Chemistry Spectroscopy Laboratory for Functional π-Electronic Systems Yonsei University 03722 Seoul Korea
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