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Jadoun D, Kowalewski M. Coherent x-ray spontaneous emission spectroscopy of conical intersections. J Chem Phys 2024; 160:094102. [PMID: 38426516 DOI: 10.1063/5.0180976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 02/16/2024] [Indexed: 03/02/2024] Open
Abstract
Conical intersections are known to play a vital role in many photochemical processes. The breakdown of the Born-Oppenheimer approximation in the vicinity of a conical intersection causes exciting phenomena, such as the ultrafast radiationless decay of excited states. The passage of a molecule through a conical intersection creates a coherent superposition of electronic states via nonadiabatic couplings. Detecting this coherent superposition may serve as a direct probe of the conical intersection. In this paper, we theoretically demonstrate the use of coherent spontaneous emission in samples with long-range order for probing the occurrence of a conical intersection in a molecule. Our simulations show that the spectrum contains clear signatures of the created coherent superposition of electronic states. We investigate the bandwidth requirements for the x-ray probes, which influence the observation of coherent superposition generated by the conical intersection.
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Affiliation(s)
- Deependra Jadoun
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden
| | - Markus Kowalewski
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden
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Jadoun D, Zhang Z, Kowalewski M. Raman Spectroscopy of Conical Intersections Using Entangled Photons. J Phys Chem Lett 2024; 15:2023-2030. [PMID: 38349969 PMCID: PMC10895689 DOI: 10.1021/acs.jpclett.3c02852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/15/2024]
Abstract
Ultrafast Raman spectroscopy with attosecond pulses in the extreme ultraviolet and X-ray regime has been proposed theoretically for tracking the non-adiabatic dynamics of molecules in great detail. The large bandwidth of these pulses, which span several electronvolts within a couple of femtoseconds, provides a unique tool for tracking non-adiabatic phenomena. However, spectroscopy with classical light is limited by the time-bandwidth product of the probe laser pulse. In this work, we theoretically investigate an ultrafast Raman spectroscopy scheme that utilizes pairs of entangled photons. Our model simulations demonstrate that the dynamics in the vicinity of a conical intersection can be resolved with unprecedented resolution in the time and frequency domain.
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Affiliation(s)
- Deependra Jadoun
- Department
of Physics, Stockholm University, AlbaNova
University Center, SE-106 91 Stockholm, Sweden
| | - Zhedong Zhang
- Department
of Physics, City University of Hong Kong, Kowloon, Hong Kong SAR
- Shenzhen
Research Institute, City University of Hong
Kong, Shenzhen, Guangdong 518057, China
| | - Markus Kowalewski
- Department
of Physics, Stockholm University, AlbaNova
University Center, SE-106 91 Stockholm, Sweden
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Abstract
The topological properties of an object, associated with an integer called the topological invariant, are global features that cannot change continuously but only through abrupt variations, hence granting them intrinsic robustness. Engineered metamaterials (MMs) can be tailored to support highly nontrivial topological properties of their band structure, relative to their electronic, electromagnetic, acoustic and mechanical response, representing one of the major breakthroughs in physics over the past decade. Here, we review the foundations and the latest advances of topological photonic and phononic MMs, whose nontrivial wave interactions have become of great interest to a broad range of science disciplines, such as classical and quantum chemistry. We first introduce the basic concepts, including the notion of topological charge and geometric phase. We then discuss the topology of natural electronic materials, before reviewing their photonic/phononic topological MM analogues, including 2D topological MMs with and without time-reversal symmetry, Floquet topological insulators, 3D, higher-order, non-Hermitian and nonlinear topological MMs. We also discuss the topological aspects of scattering anomalies, chemical reactions and polaritons. This work aims at connecting the recent advances of topological concepts throughout a broad range of scientific areas and it highlights opportunities offered by topological MMs for the chemistry community and beyond.
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Affiliation(s)
- Xiang Ni
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States
- School of Physics and Electronics, Central South University, Changsha, Hunan 410083, China
| | - Simon Yves
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States
| | - Alex Krasnok
- Department of Electrical and Computer Engineering, Florida International University, Miami, Florida 33174, USA
| | - Andrea Alù
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York, New York 10031, United States
- Department of Electrical Engineering, City College, The City University of New York, 160 Convent Avenue, New York, New York 10031, United States
- Physics Program, The Graduate Center, The City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
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Mi X, Zhang M, Zhang L, Wu C, Zhou T, Xu H, Xie C, Li Z, Liu Y. Geometric Phase Effect in Attosecond Stimulated X-ray Raman Spectroscopy. J Phys Chem A 2023; 127:3608-3613. [PMID: 37053512 DOI: 10.1021/acs.jpca.3c00594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Conical intersections (CIs) are diabolical points in the potential energy surfaces generally caused by point-wise degeneracy of different electronic states, and give rise to the geometric phases (GPs) of molecular wave functions. Here we theoretically propose and demonstrate that the transient redistribution of ultrafast electronic coherence in attosecond Raman signal (TRUECARS) spectroscopy is capable of detecting the GP effect in excited state molecules by applying two probe pulses including an attosecond and a femtosecond X-ray pulse. The mechanism is based on a set of symmetry selection rules in the presence of nontrivial GPs. The model of this work can be realized for probing the geometric phase effect in the excited state dynamics of complex molecules with appropriate symmetries, using attosecond light sources such as free-electron X-ray lasers.
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Affiliation(s)
- Xiaoyu Mi
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Ming Zhang
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Linfeng Zhang
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Chengyin Wu
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226000 China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Tianyu Zhou
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Haitan Xu
- School of Materials Science and Intelligent Engineering, Nanjing University, Suzhou, Jiangsu 215163, China
- School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China
| | - Changjian Xie
- Institute of Modern Physics, Shanxi Key Laboratory for Theoretical Physics Frontiers, Northwest University, Xi'an 710127, China
| | - Zheng Li
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226000 China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Yunquan Liu
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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Keefer D, Cavaletto SM, Rouxel JR, Garavelli M, Yong H, Mukamel S. Ultrafast X-Ray Probes of Elementary Molecular Events. Annu Rev Phys Chem 2023; 74:73-97. [PMID: 37093660 DOI: 10.1146/annurev-physchem-062322-051532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Elementary events that determine photochemical outcomes and molecular functionalities happen on the femtosecond and subfemtosecond timescales. Among the most ubiquitous events are the nonadiabatic dynamics taking place at conical intersections. These facilitate ultrafast, nonradiative transitions between electronic states in molecules that can outcompete slower relaxation mechanisms such as fluorescence. The rise of ultrafast X-ray sources, which provide intense light pulses with ever-shorter durations and larger observation bandwidths, has fundamentally revolutionized our spectroscopic capabilities to detect conical intersections. Recent theoretical studies have demonstrated an entirely new signature emerging once a molecule traverses a conical intersection, giving detailed insights into the coupled nuclear and electronic motions that underlie, facilitate, and ultimately determine the ultrafast molecular dynamics. Following a summary of current sources and experiments, we survey these techniques and provide a unified overview of their capabilities. We discuss their potential to dramatically increase our understanding of ultrafast photochemistry.
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Affiliation(s)
- Daniel Keefer
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California, USA; ,
| | - Stefano M Cavaletto
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California, USA; ,
- Current affiliation: Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Jérémy R Rouxel
- Université de Lyon, UJM-Saint-Etienne, IOGS, Laboratoire Hubert Curien, UMR CNRS 5516, Saint-Etienne, France
| | - Marco Garavelli
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Bologna, Italy
| | - Haiwang Yong
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California, USA; ,
| | - Shaul Mukamel
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California, USA; ,
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Schnappinger T, Jadoun D, Gudem M, Kowalewski M. Time-resolved X-ray and XUV based spectroscopic methods for nonadiabatic processes in photochemistry. Chem Commun (Camb) 2022; 58:12763-12781. [PMID: 36317595 PMCID: PMC9671098 DOI: 10.1039/d2cc04875b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/21/2022] [Indexed: 11/03/2023]
Abstract
The photochemistry of numerous molecular systems is influenced by conical intersections (CIs). These omnipresent nonadiabatic phenomena provide ultra-fast radiationless relaxation channels by creating degeneracies between electronic states and decide over the final photoproducts. In their presence, the Born-Oppenheimer approximation breaks down, and the timescales of the electron and nuclear dynamics become comparable. Due to the ultra-fast dynamics and the complex interplay between nuclear and electronic degrees of freedom, the direct experimental observation of nonadiabatic processes close to CIs remains challenging. In this article, we give a theoretical perspective on novel spectroscopic techniques capable of observing clear signatures of CIs. We discuss methods that are based on ultra-short laser pulses in the extreme ultraviolet and X-ray regime, as their spectral and temporal resolution allow for resolving the ultra-fast dynamics near CIs.
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Affiliation(s)
- Thomas Schnappinger
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden.
| | - Deependra Jadoun
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden.
| | - Mahesh Gudem
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden.
| | - Markus Kowalewski
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden.
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Restaino L, Jadoun D, Kowalewski M. Probing nonadiabatic dynamics with attosecond pulse trains and soft x-ray Raman spectroscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2022; 9:034101. [PMID: 35774244 PMCID: PMC9239728 DOI: 10.1063/4.0000146] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 06/06/2022] [Indexed: 05/31/2023]
Abstract
Linear off-resonant x-ray Raman techniques are capable of detecting the ultrafast electronic coherences generated when a photoexcited wave packet passes through a conical intersection. A hybrid femtosecond or attosecond probe pulse is employed to excite the system and stimulate the emission of the signal photon, where both fields are components of a hybrid pulse scheme. In this paper, we investigate how attosecond pulse trains, as provided by high-harmonic generation processes, perform as probe pulses in the framework of this spectroscopic technique, instead of single Gaussian pulses. We explore different combination schemes for the probe pulse as well as the impact of parameters of the pulse trains on the signals. Furthermore, we show how Raman selection rules and symmetry consideration affect the spectroscopic signal, and we discuss the importance of vibrational contributions to the overall signal. We use two different model systems, representing molecules of different symmetries, and quantum dynamics simulations to study the difference in the spectra. The results suggest that such pulse trains are well suited to capture the key features associated with the electronic coherence.
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