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Sviyazov SV, Babenko SV, Skovpin IV, Kovtunova LM, Chukanov NV, Stakheev AY, Burueva DB, Koptyug IV. Manipulating stereoselectivity of parahydrogen addition to acetylene to unravel interconversion of ethylene nuclear spin isomers. Phys Chem Chem Phys 2024; 26:7821-7829. [PMID: 38375632 DOI: 10.1039/d3cp04983c] [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
Symmetric molecules exist as distinct nuclear spin isomers (NSIMs). A deeper understanding of their properties, including interconversion of different NSIMs, requires efficient techniques for NSIM enrichment. In this work, selective hydrogenation of acetylene with parahydrogen (p-H2) was used to achieve the enrichment of ethylene NSIMs and to study their equilibration processes. The effect of the stereoselectivity of H2 addition to acetylene on the imbalance of ethylene NSIMs was experimentally demonstrated by using three different heterogeneous catalysts (an immobilized Ir complex and two supported Pd catalysts). The interconversion of NSIMs with time during ethylene storage was studied using NMR spectroscopy by reacting ethylene with bromine water, which rendered the p-H2-derived protons in the produced 2-bromoethan(2H)ol (BrEtOD) magnetically inequivalent, thereby revealing the non-equilibrium nuclear spin order of ethylene. A thorough analysis of the shape and transformation of the 1H NMR spectra of hyperpolarized BrEtOD allowed us to reveal the initial distribution of produced ethylene NSIMs and their equilibration processes. Comparison of the results obtained with three different catalysts was key to properly attributing the derived characteristic time constants to different ethylene NSIM interconversion processes: ∼3-6 s for interconversion between NSIMs with the same inversion symmetry (i.e., within g or u manifolds) and ∼1700-2200 s between NSIMs with different inversion symmetries (i.e., between g and u manifolds).
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Affiliation(s)
- Sergey V Sviyazov
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, Novosibirsk 630090, Russia.
- Novosibirsk State University, Novosibirsk 630090, Russia
| | - Simon V Babenko
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, Novosibirsk 630090, Russia.
- V.V. Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, Novosibirsk 630090, Russia
| | - Ivan V Skovpin
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, Novosibirsk 630090, Russia.
| | - Larisa M Kovtunova
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, Novosibirsk 630090, Russia.
- Boreskov Institute of Catalysis, SB RAS, Novosibirsk 630090, Russia
| | - Nikita V Chukanov
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, Novosibirsk 630090, Russia.
- Novosibirsk State University, Novosibirsk 630090, Russia
| | | | - Dudari B Burueva
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, Novosibirsk 630090, Russia.
| | - Igor V Koptyug
- Laboratory of Magnetic Resonance Microimaging, International Tomography Center, SB RAS, Novosibirsk 630090, Russia.
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2
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Sitha S. Ortho-para interconversion of nuclear states of H 2O through replica transition state: prospect of quantum entanglement at homodromic Bjerrum defect site. J Mol Model 2023; 29:242. [PMID: 37436555 PMCID: PMC10338397 DOI: 10.1007/s00894-023-05646-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/01/2023] [Indexed: 07/13/2023]
Abstract
CONTEXT From a nuclear spin prospective, water exists as para and ortho nuclear spin isomers (isotopomers). Spin interconversions in isolated molecules of water are forbidden, but many recent reports have shown them to happen in bulk, through dynamic proton exchanges happening between interconnected networks of a large array of water molecules. In this contribution, a possible explanation for an unexpected slow or delayed interconversion of ortho-para water in ice observed in an earlier reported experiment is provided. Using the results of quantum mechanical investigations, we have discussed the roles played by Bjerrum defects in the dynamic proton exchanges and ortho-para spin state interconversions. We guess that at the sites of the Bjerrum defects, there are possibilities of quantum entanglements of states, through pairwise interactions. Based on the perfectly correlated exchange happening via a replica transition state, we speculate that it can have significant influences on ortho-para interconversions of water. We also conjecture that the overall ortho-para interconversion is not a continuous process, rather can be imagined to be happening serendipitously, but within the boundary of the rules of quantum mechanics. METHODS All computations were performed with Gaussian 09 program. B3LYP/6-31++G(d,p) methodology was used to compute all the stationary points. Further energy corrections were computed using CCSD(T)/aug-cc-pVTZ methodology. Intrinsic reaction coordinate (IRC) path computations were carried out for the transition states.
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Affiliation(s)
- Sanyasi Sitha
- Department of Chemical Sciences, APK Campus, University of Johannesburg, PO Box 524, Auckland Park, Johannesburg, 2006, South Africa.
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3
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Pokochueva EV, Svyatova AI, Burueva DB, Koptyug IV. Chemistry of nuclear spin isomers of the molecules: from the past of the Universe to emerging technologies. Russ Chem Bull 2023. [DOI: 10.1007/s11172-023-3711-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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4
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Yachmenev A, Yang G, Zak E, Yurchenko S, Küpper J. The nuclear-spin-forbidden rovibrational transitions of water from first principles. J Chem Phys 2022; 156:204307. [DOI: 10.1063/5.0090771] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The water molecule occurs in two nuclear-spin isomers that differ by the value of the total nuclear spin of the hydrogen atoms, i.e., I = 0 for para-H2O and I = 1 for ortho-H2O. Spectroscopic transitions between rovibrational states of ortho and para water are extremely weak due to the tiny hyperfine nuclear-spin –rotation interaction of only ∼30 kHz and, so far, have not been observed. We report the first comprehensive theoretical investigation of the hyperfine effects and ortho–para transitions in [Formula: see text]O due to nuclear-spin –rotation and spin–spin interactions. We also present the details of our newly developed general variational approach to the simulation of hyperfine effects in polyatomic molecules. Our results for water suggest that the strongest ortho–para transitions with room-temperature intensities on the order of 10−31 cm/molecule are about an order of magnitude larger than previously predicted values and should be detectable in the mid-infrared ν2 and near-infrared 2 ν1 + ν2 and ν1 + ν2 + ν3 bands by current spectroscopy experiments.
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Affiliation(s)
- Andrey Yachmenev
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Guang Yang
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Emil Zak
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Sergei Yurchenko
- Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - Jochen Küpper
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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5
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Wespiser C, Putaud T, Kalugina YN, Soldera A, Roy PN, Michaut X, Ayotte P. Ro-translational dynamics of confined water: I - The confined asymmetric rotor model. J Chem Phys 2022; 156:074304. [DOI: 10.1063/5.0079565] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Thomas Putaud
- Universite de Sherbrooke Departement de chimie, Canada
| | | | - Armand Soldera
- Department of Chemistry, Universite de Sherbrooke, Canada
| | - Pierre-Nicholas Roy
- Department of Chemistry, University of Waterloo Department of Chemistry, Canada
| | | | - Patrick Ayotte
- Département de Chimie, Universite de Sherbrooke Departement de chimie, Canada
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6
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Putaud T, Wespiser C, Bertin M, Fillion JH, Kalugina YN, Jeseck P, Milpanis A, Philippe L, Soulard P, Tremblay B, Tuloup C, Ayotte P, Michaut X. Ro-translational dynamics of confined water: II - Spectroscopic evidence of confinement effects on the far-infrared spectra of water isotopologues in argon and krypton matrices. J Chem Phys 2022; 156:074305. [DOI: 10.1063/5.0079566] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thomas Putaud
- Universite de Sherbrooke Departement de chimie, Canada
| | | | | | | | | | | | | | | | | | | | | | - Patrick Ayotte
- Département de Chimie, Universite de Sherbrooke Departement de chimie, Canada
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7
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Macroscopic production of highly nuclear-spin-polarized molecules from IR-excitation and photodissociation of molecular beams. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.139092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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8
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Nagaya Y, Nakatsu H, Ogura S, Shimazaki K, Ueta H, Takeyasu K, Fukutani K. Focusing and spin polarization of atomic hydrogen beam. J Chem Phys 2021; 155:194201. [PMID: 34800952 DOI: 10.1063/5.0068251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have developed a spin-polarized-hydrogen beam with a hexapole magnet. By combining the beam chopper and pulsed laser ionization detection, the time-of-flight of the hydrogen beam was measured, and the dependence of the beam profile on the velocity was acquired, which was consistent with the beam trajectory simulations. The spin polarization of the beam was analyzed by using the Stern-Gerlach-type magnet in combination with the spatial scan of the detection laser. The spin polarization was about 95% at a focusing condition due to the hexapole magnet. The polarization was, on the other hand, reduced to about 70% for the beam at higher velocities, which is consistent with simulation results.
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Affiliation(s)
- Y Nagaya
- Institute of Industrial Science, The University of Tokyo, Komaba Meguro-ku, Tokyo 153-8 505, Japan
| | - H Nakatsu
- Institute of Industrial Science, The University of Tokyo, Komaba Meguro-ku, Tokyo 153-8 505, Japan
| | - S Ogura
- School of Engineering, Tokyo Denki University, Senju 5 Asahi-cho, Adachi-ku, Tokyo 120-8 551, Japan
| | - K Shimazaki
- Institute of Industrial Science, The University of Tokyo, Komaba Meguro-ku, Tokyo 153-8 505, Japan
| | - H Ueta
- Advanced Science Research Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1 195, Japan
| | - K Takeyasu
- Institute of Industrial Science, The University of Tokyo, Komaba Meguro-ku, Tokyo 153-8 505, Japan
| | - K Fukutani
- Institute of Industrial Science, The University of Tokyo, Komaba Meguro-ku, Tokyo 153-8 505, Japan
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9
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Holst B, Alexandrowicz G, Avidor N, Benedek G, Bracco G, Ernst WE, Farías D, Jardine AP, Lefmann K, Manson JR, Marquardt R, Artés SM, Sibener SJ, Wells JW, Tamtögl A, Allison W. Material properties particularly suited to be measured with helium scattering: selected examples from 2D materials, van der Waals heterostructures, glassy materials, catalytic substrates, topological insulators and superconducting radio frequency materials. Phys Chem Chem Phys 2021; 23:7653-7672. [PMID: 33625410 DOI: 10.1039/d0cp05833e] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Helium Atom Scattering (HAS) and Helium Spin-Echo scattering (HeSE), together helium scattering, are well established, but non-commercial surface science techniques. They are characterised by the beam inertness and very low beam energy (<0.1 eV) which allows essentially all materials and adsorbates, including fragile and/or insulating materials and light adsorbates such as hydrogen to be investigated on the atomic scale. At present there only exist an estimated less than 15 helium and helium spin-echo scattering instruments in total, spread across the world. This means that up till now the techniques have not been readily available for a broad scientific community. Efforts are ongoing to change this by establishing a central helium scattering facility, possibly in connection with a neutron or synchrotron facility. In this context it is important to clarify what information can be obtained from helium scattering that cannot be obtained with other surface science techniques. Here we present a non-exclusive overview of a range of material properties particularly suited to be measured with helium scattering: (i) high precision, direct measurements of bending rigidity and substrate coupling strength of a range of 2D materials and van der Waals heterostructures as a function of temperature, (ii) direct measurements of the electron-phonon coupling constant λ exclusively in the low energy range (<0.1 eV, tuneable) for 2D materials and van der Waals heterostructures (iii) direct measurements of the surface boson peak in glassy materials, (iv) aspects of polymer chain surface dynamics under nano-confinement (v) certain aspects of nanoscale surface topography, (vi) central properties of surface dynamics and surface diffusion of adsorbates (HeSE) and (vii) two specific science case examples - topological insulators and superconducting radio frequency materials, illustrating how combined HAS and HeSE are necessary to understand the properties of quantum materials. The paper finishes with (viii) examples of molecular surface scattering experiments and other atom surface scattering experiments which can be performed using HAS and HeSE instruments.
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Affiliation(s)
- Bodil Holst
- Department of Physics and Technology, University of Bergen, Allegaten 55, 5007 Bergen, Norway.
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10
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Ellermann F, Pravdivtsev A, Hövener JB. Open-source, partially 3D-printed, high-pressure (50-bar) liquid-nitrogen-cooled parahydrogen generator. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:49-62. [PMID: 37904754 PMCID: PMC10539807 DOI: 10.5194/mr-2-49-2021] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 12/15/2020] [Indexed: 11/01/2023]
Abstract
The signal of magnetic resonance imaging (MRI) can be enhanced by several orders of magnitude using hyperpolarization. In comparison to a broadly used dynamic nuclear polarization (DNP) technique that is already used in clinical trials, the parahydrogen (p H2 ) -based hyperpolarization approaches are less cost-intensive, are scalable, and offer high throughput. However, a p H2 generator is necessary. Available commercial p H2 generators are relatively expensive (EUR 10 000-150 000). To facilitate the spread of p H2 -based hyperpolarization studies, here we provide the blueprints and 3D models as open-source for a low-cost (EUR < 3000 ) 50-bar liquid-nitrogen-cooled p H2 generator.
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Affiliation(s)
- Frowin Ellermann
- Section for Biomedical Imaging, Molecular Imaging North Competence
Center (MOIN CC), Department of Radiology and Neuroradiology, University
Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel 24118, Germany
| | - Andrey Pravdivtsev
- Section for Biomedical Imaging, Molecular Imaging North Competence
Center (MOIN CC), Department of Radiology and Neuroradiology, University
Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel 24118, Germany
| | - Jan-Bernd Hövener
- Section for Biomedical Imaging, Molecular Imaging North Competence
Center (MOIN CC), Department of Radiology and Neuroradiology, University
Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel 24118, Germany
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11
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Zhukov SS, Balos V, Hoffman G, Alom S, Belyanchikov M, Nebioglu M, Roh S, Pronin A, Bacanu GR, Abramov P, Wolf M, Dressel M, Levitt MH, Whitby RJ, Gorshunov B, Sajadi M. Rotational coherence of encapsulated ortho and para water in fullerene-C 60 revealed by time-domain terahertz spectroscopy. Sci Rep 2020; 10:18329. [PMID: 33110105 PMCID: PMC7592058 DOI: 10.1038/s41598-020-74972-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/06/2020] [Indexed: 11/15/2022] Open
Abstract
We resolve the real-time coherent rotational motion of isolated water molecules encapsulated in fullerene-C60 cages by time-domain terahertz (THz) spectroscopy. We employ single-cycle THz pulses to excite the low-frequency rotational motion of water and measure the subsequent coherent emission of electromagnetic waves by water molecules. At temperatures below ~ 100 K, C60 lattice vibrational damping is mitigated and the quantum dynamics of confined water are resolved with a markedly long rotational coherence, extended beyond 10 ps. The observed rotational transitions agree well with low-frequency rotational dynamics of single water molecules in the gas phase. However, some additional spectral features with their major contribution at ~2.26 THz are also observed which may indicate interaction between water rotation and the C60 lattice phonons. We also resolve the real-time change of the emission pattern of water after a sudden cooling to 4 K, signifying the conversion of ortho-water to para-water over the course of 10s hours. The observed long coherent rotational dynamics of isolated water molecules confined in C60 makes this system an attractive candidate for future quantum technology.
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Affiliation(s)
| | | | | | - Shamim Alom
- School of Chemistry, University of Southampton, Southampton, UK
| | | | - Mehmet Nebioglu
- 1. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
| | - Seulki Roh
- 1. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
| | - Artem Pronin
- 1. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
| | - George R Bacanu
- School of Chemistry, University of Southampton, Southampton, UK
| | - Pavel Abramov
- Moscow Institute of Physics and Technology, Moscow, Russia
| | - Martin Wolf
- Fritz-Haber-Institut der MPG, Berlin, Germany
| | - Martin Dressel
- Moscow Institute of Physics and Technology, Moscow, Russia
- 1. Physikalisches Institut, Universität Stuttgart, Stuttgart, Germany
| | | | | | | | - Mohsen Sajadi
- Fritz-Haber-Institut der MPG, Berlin, Germany.
- Department of Chemistry, University of Paderborn, Paderborn, Germany.
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12
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Mitra D, Vilas NB, Hallas C, Anderegg L, Augenbraun BL, Baum L, Miller C, Raval S, Doyle JM. Direct laser cooling of a symmetric top molecule. Science 2020; 369:1366-1369. [DOI: 10.1126/science.abc5357] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/10/2020] [Indexed: 11/02/2022]
Abstract
Ultracold polyatomic molecules have potentially wide-ranging applications in quantum simulation and computation, particle physics, and quantum chemistry. For atoms and small molecules, direct laser cooling has proven to be a powerful tool for quantum science in the ultracold regime. However, the feasibility of laser-cooling larger, nonlinear polyatomic molecules has remained unknown because of their complex structure. We laser-cooled the symmetric top molecule calcium monomethoxide (CaOCH3), reducing the temperature of ~104 molecules from 22 ± 1 millikelvin to 1.8 ± 0.7 millikelvin in one dimension and state-selectively cooling two nuclear spin isomers. These results demonstrate that the use of proper ro-vibronic transitions enables laser cooling of nonlinear molecules, thereby opening a path to efficient cooling of chiral molecules and, eventually, optical tweezer arrays of complex polyatomic species.
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Affiliation(s)
- Debayan Mitra
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Nathaniel B. Vilas
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Christian Hallas
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Loïc Anderegg
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Benjamin L. Augenbraun
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Louis Baum
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Calder Miller
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Shivam Raval
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - John M. Doyle
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
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13
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Setting benchmarks for modelling gas-surface interactions using coherent control of rotational orientation states. Nat Commun 2020; 11:3110. [PMID: 32561837 PMCID: PMC7305202 DOI: 10.1038/s41467-020-16930-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/02/2020] [Indexed: 11/09/2022] Open
Abstract
The coherent evolution of a molecular quantum state during a molecule-surface collision is a detailed descriptor of the interaction potential which was so far inaccessible to measurements. Here we use a magnetically controlled molecular beam technique to study the collision of rotationally oriented ground state hydrogen molecules with a lithium fluoride surface. The coherent control nature of the technique allows us to measure the changes in the complex amplitudes of the rotational projection quantum states, and express them using a scattering matrix formalism. The quantum state-to-state transition probabilities we extract reveal a strong dependency of the molecule-surface interaction on the rotational orientation of the molecules, and a remarkably high probability of the collision flipping the rotational orientation. The scattering matrix we obtain from the experimental data delivers an ultra-sensitive benchmark for theory to reproduce, guiding the development of accurate theoretical models for the interaction of H2 with a solid surface. A fundamental and predictive understanding of molecule-surface interactions is challenging to obtain. Here the authors report an experimental technique allowing direct measurement of the scattering matrix, which reports on the coherent evolution of quantum states of a molecule scattering from a surface.
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14
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Vermette J, Braud I, Turgeon PA, Alexandrowicz G, Ayotte P. Quantum State-Resolved Characterization of a Magnetically Focused Beam of ortho-H2O. J Phys Chem A 2019; 123:9234-9239. [DOI: 10.1021/acs.jpca.9b04294] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jonathan Vermette
- Département de Chimie, Université de Sherbrooke, 2500 boulevard de l’Université, J1K2R1 Sherbrooke, Canada
| | - Isabelle Braud
- Département de Chimie, Université de Sherbrooke, 2500 boulevard de l’Université, J1K2R1 Sherbrooke, Canada
| | - Pierre-Alexandre Turgeon
- Département de Chimie, Université de Sherbrooke, 2500 boulevard de l’Université, J1K2R1 Sherbrooke, Canada
| | | | - Patrick Ayotte
- Département de Chimie, Université de Sherbrooke, 2500 boulevard de l’Université, J1K2R1 Sherbrooke, Canada
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15
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Toscano J, Rennick CJ, Softley TP, Heazlewood BR. A magnetic guide to purify radical beams. J Chem Phys 2018; 149:174201. [DOI: 10.1063/1.5053656] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Jutta Toscano
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | | | | | - Brianna R. Heazlewood
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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16
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Krüger C, Lisitsin-Baranovsky E, Ofer O, Turgeon PA, Vermette J, Ayotte P, Alexandrowicz G. A magnetically focused molecular beam source for deposition of spin-polarised molecular surface layers. J Chem Phys 2018; 149:164201. [PMID: 30384725 DOI: 10.1063/1.5048521] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Separating molecular spin isomers is a challenging task, with potential applications in various fields ranging from astrochemistry to magnetic resonance imaging. A new promising method for spin-isomer separation is magnetic focusing, a method which was shown to be capable of producing a molecular beam of ortho-water. Here, we present results from a modified magnetic focusing apparatus and show that it can be used to separate the spin isomers of acetylene and methane. From the measured focused profiles of the molecular beams and a numerical simulation analysis, we provide estimations for the spin purity and the significantly improved molecular flux obtained with the new setup. Finally, we discuss the spin-relaxation conditions which will be needed to apply this new source for measuring nuclear magnetic resonance signals of a single surface layer.
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Affiliation(s)
- C Krüger
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - E Lisitsin-Baranovsky
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - O Ofer
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - P-A Turgeon
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec J1K 2R1, Canada
| | - J Vermette
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec J1K 2R1, Canada
| | - P Ayotte
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec J1K 2R1, Canada
| | - G Alexandrowicz
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
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17
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Meier B, Kouřil K, Bengs C, Kouřilová H, Barker TC, Elliott SJ, Alom S, Whitby RJ, Levitt MH. Spin-Isomer Conversion of Water at Room Temperature and Quantum-Rotor-Induced Nuclear Polarization in the Water-Endofullerene H_{2}O@C_{60}. PHYSICAL REVIEW LETTERS 2018; 120:266001. [PMID: 30004780 DOI: 10.1103/physrevlett.120.266001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/24/2018] [Indexed: 05/15/2023]
Abstract
Water exists in two forms, para and ortho, that have nuclear spin states with different symmetries. Here we report the conversion of fullerene-encapsulated para water to ortho water. The enrichment of para water at low temperatures is monitored via changes in the electrical polarizability of the material. Upon rapid dissolution of the material in toluene the excess para water converts to ortho water. In H_{2}^{16}O@C_{60} the conversion leads to a slow increase in the NMR signal. In H_{2}^{17}O@C_{60} the conversion gives rise to weak signal enhancements attributed to quantum-rotor-induced nuclear spin polarization. The time constants for the para-to-ortho conversion of fullerene-encapsulated water in ambient temperature solution are estimated as 30±4 s for the ^{16}O isotopolog of water, and 16±3 s for the ^{17}O isotopolog.
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Affiliation(s)
- Benno Meier
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Karel Kouřil
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Christian Bengs
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Hana Kouřilová
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Timothy C Barker
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Stuart J Elliott
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Shamim Alom
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Richard J Whitby
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Malcolm H Levitt
- School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
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18
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19
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Observation of different reactivities of para and ortho-water towards trapped diazenylium ions. Nat Commun 2018; 9:2096. [PMID: 29844308 PMCID: PMC5974139 DOI: 10.1038/s41467-018-04483-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 04/27/2018] [Indexed: 11/08/2022] Open
Abstract
Water is one of the most fundamental molecules in chemistry, biology and astrophysics. It exists as two distinct nuclear-spin isomers, para- and ortho-water, which do not interconvert in isolated molecules. The experimental challenges in preparing pure samples of the two isomers have thus far precluded a characterization of their individual chemical behavior. Capitalizing on recent advances in the electrostatic deflection of polar molecules, we separate the ground states of para- and ortho-water in a molecular beam to show that the two isomers exhibit different reactivities in a prototypical reaction with trapped diazenylium ions. Based on ab initio calculations and a modelling of the reaction kinetics using rotationally adiabatic capture theory, we rationalize this finding in terms of different rotational averaging of ion-dipole interactions during the reaction. Water molecules exist as two distinct nuclear-spin isomers denoted ortho and para. Here, the authors separate these two isomers in the gas phase to show that they exhibit different reactivities in a prototypical proton-transfer reaction.
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21
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Discrimination of 1,1-difluoroethylene nuclear spin isomers in the presence of non-adiabatic coupling terms. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.03.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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22
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Godsi O, Corem G, Alkoby Y, Cantin JT, Krems RV, Somers MF, Meyer J, Kroes GJ, Maniv T, Alexandrowicz G. A general method for controlling and resolving rotational orientation of molecules in molecule-surface collisions. Nat Commun 2017; 8:15357. [PMID: 28480890 PMCID: PMC5424257 DOI: 10.1038/ncomms15357] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/14/2017] [Indexed: 11/23/2022] Open
Abstract
The outcome of molecule–surface collisions can be modified by pre-aligning the molecule; however, experiments accomplishing this are rare because of the difficulty of preparing molecules in aligned quantum states. Here we present a general solution to this problem based on magnetic manipulation of the rotational magnetic moment of the incident molecule. We apply the technique to the scattering of H2 from flat and stepped copper surfaces. We demonstrate control of the molecule's initial quantum state, allowing a direct comparison of differences in the stereodynamic scattering from the two surfaces. Our results show that a stepped surface exhibits a much larger dependence of the corrugation of the interaction on the alignment of the molecule than the low-index surface. We also demonstrate an extension of the technique that transforms the set-up into an interferometer, which is sensitive to molecular quantum states both before and after the scattering event. The rotational orientation of a molecule plays a fundamental role in molecule-surface collisions, yet is difficult to study. Here, the authors present a general approach for controlling and resolving molecular rotational orientation and apply it to study H2 scattering from flat and stepped copper surfaces.
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Affiliation(s)
- Oded Godsi
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Gefen Corem
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Yosef Alkoby
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Joshua T Cantin
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - Roman V Krems
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - Mark F Somers
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Jörg Meyer
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Geert-Jan Kroes
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Tsofar Maniv
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Gil Alexandrowicz
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
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Liu Y, Vashishta M, Djuricanin P, Zhou S, Zhong W, Mittertreiner T, Carty D, Momose T. Magnetic Trapping of Cold Methyl Radicals. PHYSICAL REVIEW LETTERS 2017; 118:093201. [PMID: 28306318 DOI: 10.1103/physrevlett.118.093201] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Indexed: 06/06/2023]
Abstract
We have demonstrated that a supersonic beam of methyl radicals (CH_{3}) in the ground rotational state of both para and ortho species has been slowed down to standstill with a magnetic molecular decelerator, and successfully captured spatially in an anti-Helmholtz magnetic trap for >1 s. The trapped CH_{3} radicals have a mean translational temperature of about 200 mK with an estimated density of >5.0×10^{7} cm^{-3}. The methyl radical is an ideal system for the study of cold molecules not only because of its high reactivities at low temperatures, but also because further cooling below 1 mK is plausible via sympathetic cooling with ultracold atoms. The demonstrated trapping capability of methyl radicals opens up various possibilities for realizing ultracold ensembles of molecules towards Bose-Einstein condensation of polyatomic molecules and investigations of reactions governed by quantum statistics.
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Affiliation(s)
- Yang Liu
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Manish Vashishta
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Pavle Djuricanin
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Sida Zhou
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Wei Zhong
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Tony Mittertreiner
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - David Carty
- Durham University, Joint Quantum Centre Durham-Newcastle, Departments of Chemistry and Physics, South Road, Durham DH1 3LE, United Kingdom
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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24
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Turgeon PA, Vermette J, Alexandrowicz G, Peperstraete Y, Philippe L, Bertin M, Fillion JH, Michaut X, Ayotte P. Confinement Effects on the Nuclear Spin Isomer Conversion of H 2O. J Phys Chem A 2017; 121:1571-1576. [PMID: 28157310 DOI: 10.1021/acs.jpca.7b00893] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mechanism for interconversion between the nuclear spin isomers (NSI) of H2O remains shrouded in uncertainties. The temperature dependence displayed by NSI interconversion rates for H2O isolated in an argon matrix provides evidence that confinement effects are responsible for the dramatic increase in their kinetics with respect to the gas phase, providing new pathways for o-H2O↔p-H2O conversion in endohedral compounds. This reveals intramolecular aspects of the interconversion mechanism which may improve methodologies for the separation and storage of NSI en route to applications ranging from magnetic resonance spectroscopy and imaging to interpretations of spin temperatures in the interstellar medium.
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Affiliation(s)
| | - Jonathan Vermette
- Département de Chimie, Université de Sherbrooke , Sherbrooke J1K 2R1, Canada
| | - Gil Alexandrowicz
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology , Technion City, Haifa 32000, Israel
| | - Yoann Peperstraete
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06 , F-75252 Paris, France
| | - Laurent Philippe
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06 , F-75252 Paris, France
| | - Mathieu Bertin
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06 , F-75252 Paris, France
| | - Jean-Hugues Fillion
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06 , F-75252 Paris, France
| | - Xavier Michaut
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Université Paris 06 , F-75252 Paris, France
| | - Patrick Ayotte
- Département de Chimie, Université de Sherbrooke , Sherbrooke J1K 2R1, Canada
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25
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Collisional cross-section of water molecules in vapour studied by means of 1H relaxation in NMR. Sci Rep 2016; 6:38492. [PMID: 28008913 PMCID: PMC5180102 DOI: 10.1038/srep38492] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 11/11/2016] [Indexed: 11/08/2022] Open
Abstract
In gas phase, collisions that affect the rotational angular momentum lead to the return of the magnetization to its equilibrium (relaxation) in Nuclear Magnetic Resonance (NMR). To the best of our knowledge, the longitudinal relaxation rates R1 = 1/T1 of protons in H2O and HDO have never been measured in gas phase. We report R1 in gas phase in a field of 18.8 T, i.e., at a proton Larmor frequency ν0 = 800 MHz, at temperatures between 353 and 373 K and pressures between 9 and 101 kPa. By assuming that spin rotation is the dominant relaxation mechanism, we estimated the effective cross-section σJ for the transfer of angular momentum due to H2O-H2O and HDO-D2O collisions. Our results allow one to test theoretical predictions of the intermolecular potential of water in gas phase.
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26
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Waldl M, Oppel M, González L. Controlling the Excited-State Dynamics of Nuclear Spin Isomers Using the Dynamic Stark Effect. J Phys Chem A 2016; 120:4907-14. [PMID: 26840424 DOI: 10.1021/acs.jpca.5b12542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Stark control of chemical reactions uses intense laser pulses to distort the potential energy surfaces of a molecule, thus opening new chemical pathways. We use the concept of Stark shifts to convert a local minimum into a local maximum of the potential energy surface, triggering constructive and destructive wave-packet interferences, which then induce different dynamics on nuclear spin isomers in the electronically excited state of a quinodimethane derivative. Model quantum-dynamical simulations on reduced dimensionality using optimized ultrashort laser pulses demonstrate a difference of the excited-state dynamics of two sets of nuclear spin isomers, which ultimately can be used to discriminate between these isomers.
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Affiliation(s)
- Maria Waldl
- Institut für Theoretische Chemie, Universität Wien , Währinger Str. 17, 1090 Wien, Austria
| | - Markus Oppel
- Institut für Theoretische Chemie, Universität Wien , Währinger Str. 17, 1090 Wien, Austria
| | - Leticia González
- Institut für Theoretische Chemie, Universität Wien , Währinger Str. 17, 1090 Wien, Austria
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27
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Mammoli D, Salvi N, Milani J, Buratto R, Bornet A, Sehgal AA, Canet E, Pelupessy P, Carnevale D, Jannin S, Bodenhausen G. Challenges in preparing, preserving and detecting para-water in bulk: overcoming proton exchange and other hurdles. Phys Chem Chem Phys 2016; 17:26819-27. [PMID: 26399171 DOI: 10.1039/c5cp03350k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Para-water is an analogue of para-hydrogen, where the two proton spins are in a quantum state that is antisymmetric under permutation, also known as singlet state. The populations of the nuclear spin states in para-water are believed to have long lifetimes just like other Long-Lived States (LLSs). This hypothesis can be verified by measuring the relaxation of an excess or a deficiency of para-water, also known as a "Triplet-Singlet Imbalance" (TSI), i.e., a difference between the average population of the three triplet states T (that are symmetric under permutation) and the population of the singlet state S. In analogy with our recent findings on ethanol and fumarate, we propose to adapt the procedure for Dissolution Dynamic Nuclear Polarization (D-DNP) to prepare such a TSI in frozen water at very low temperatures in the vicinity of 1.2 K. After rapid heating and dissolution using an aprotic solvent, the TSI should be largely preserved. To assess this hypothesis, we studied the lifetime of water as a molecular entity when diluted in various solvents. In neat liquid H2O, proton exchange rates have been characterized by spin-echo experiments on oxygen-17 in natural abundance, with and without proton decoupling. One-dimensional exchange spectroscopy (EXSY) has been used to study proton exchange rates in H2O, HDO and D2O mixtures diluted in various aprotic solvents. In the case of 50 mM H2O in dioxane-d8, the proton exchange lifetime is about 20 s. After dissolving, one can observe this TSI by monitoring intensities in oxygen-17 spectra of H2O (if necessary using isotopically enriched samples) where the AX2 system comprising a "spy" oxygen A and two protons X2 gives rise to binomial multiplets only if the TSI vanishes. Alternatively, fast chemical addition to a suitable substrate (such as an activated aldehyde or ketone) can provide AX2 systems where a carbon-13 acts as a spy nucleus. Proton signals that relax to equilibrium with two distinct time constants can be considered as a hallmark of a TSI. We optimized several experimental procedures designed to preserve and reveal dilute para-water in bulk.
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Affiliation(s)
- Daniele Mammoli
- Institut des Sciences et Ingéniérie Chimiques, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
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Hama T, Kouchi A, Watanabe N. Statistical ortho-to-para ratio of water desorbed from ice at 10 kelvin. Science 2016; 351:65-7. [DOI: 10.1126/science.aad4026] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Tetsuya Hama
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060–0819, Japan
| | - Akira Kouchi
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060–0819, Japan
| | - Naoki Watanabe
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060–0819, Japan
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29
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Meier B, Mamone S, Concistrè M, Alonso-Valdesueiro J, Krachmalnicoff A, Whitby RJ, Levitt MH. Electrical detection of ortho-para conversion in fullerene-encapsulated water. Nat Commun 2015; 6:8112. [PMID: 26299447 PMCID: PMC4560827 DOI: 10.1038/ncomms9112] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 07/20/2015] [Indexed: 01/01/2023] Open
Abstract
Water exists in two spin isomers, ortho and para, that have different nuclear spin states. In bulk water, rapid proton exchange and hindered molecular rotation obscure the direct observation of two spin isomers. The supramolecular endofullerene H2O@C60 provides freely rotating, isolated water molecules even at cryogenic temperatures. Here we show that the bulk dielectric constant of this substance depends on the ortho/para ratio, and changes slowly in time after a sudden temperature jump, due to nuclear spin conversion. The attribution of the effect to ortho-para conversion is validated by comparison with nuclear magnetic resonance and quantum theory. The change in dielectric constant is consistent with an electric dipole moment of 0.51±0.05 Debye for an encapsulated water molecule, indicating the partial shielding of the water dipole by the encapsulating cage. The dependence of bulk dielectric constant on nuclear spin isomer composition appears to be a previously unreported physical phenomenon.
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Affiliation(s)
- Benno Meier
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Salvatore Mamone
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Maria Concistrè
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | | | | | - Richard J. Whitby
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Malcolm H. Levitt
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
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30
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Separation and conversion dynamics of nuclear-spin isomers of gaseous methanol. Nat Commun 2015; 6:6877. [PMID: 25880882 PMCID: PMC4411283 DOI: 10.1038/ncomms7877] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 03/06/2015] [Indexed: 11/08/2022] Open
Abstract
All symmetrical molecules with non-zero nuclear spin exist in nature as nuclear-spin isomers (NSIs). However, owing to the lack of experimental information, knowledge is rare about interconversions of NSIs of gaseous molecules with torsional symmetry. Here we report our separation and conversion observations on NSI-torsion-specific transition systems of gaseous methanol from a light-induced drift experiment involving partially spatial separation of the ortho and para isomers. We find that vibrationally excited molecules of the methanol spin isomer have a smaller collision cross-section than their ground-state counterparts. Interconversion of the enriched ortho isomer with the para isomer, which is generally considered improbable, has been quantitatively studied by sensitive detections of the spectral intensities. Rather counterintuitively, this reveals that the interconversion is inhibited with increasing pressure. Our results suggest that the spin conversion mechanism in methanol is via a quantum relaxation process with the quantum Zeno effect induced by molecular collisions. The conversion dynamics of nuclear-spin isomers has only been observed for a small number of molecules, generally with rotational symmetry. Here, the authors observe the separation of nuclear-spin isomers of gaseous methanol and show a decreased interconversion at higher pressures.
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Mamone S, Concistrè M, Carignani E, Meier B, Krachmalnicoff A, Johannessen OG, Lei X, Li Y, Denning M, Carravetta M, Goh K, Horsewill AJ, Whitby RJ, Levitt MH. Nuclear spin conversion of water inside fullerene cages detected by low-temperature nuclear magnetic resonance. J Chem Phys 2014; 140:194306. [PMID: 24852537 DOI: 10.1063/1.4873343] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The water-endofullerene H2O@C60 provides a unique chemical system in which freely rotating water molecules are confined inside homogeneous and symmetrical carbon cages. The spin conversion between the ortho and para species of the endohedral H2O was studied in the solid phase by low-temperature nuclear magnetic resonance. The experimental data are consistent with a second-order kinetics, indicating a bimolecular spin conversion process. Numerical simulations suggest the simultaneous presence of a spin diffusion process allowing neighbouring ortho and para molecules to exchange their angular momenta. Cross-polarization experiments found no evidence that the spin conversion of the endohedral H2O molecules is catalysed by (13)C nuclei present in the cages.
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Affiliation(s)
- Salvatore Mamone
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Maria Concistrè
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Elisa Carignani
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Benno Meier
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Andrea Krachmalnicoff
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Ole G Johannessen
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Xuegong Lei
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Yongjun Li
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Mark Denning
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Marina Carravetta
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Kelvin Goh
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Anthony J Horsewill
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Richard J Whitby
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Malcolm H Levitt
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
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34
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Horke DA, Chang YP, Długołęcki K, Küpper J. SeparatingParaandOrthoWater. Angew Chem Int Ed Engl 2014; 53:11965-8. [DOI: 10.1002/anie.201405986] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Indexed: 11/09/2022]
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35
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Carnevale D, Ashbrook SE, Bodenhausen G. Solid-state NMR measurements and DFT calculations of the magnetic shielding tensors of protons of water trapped in barium chlorate monohydrate. RSC Adv 2014. [DOI: 10.1039/c4ra09992c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The magnetic shielding tensors of protons of water in barium chlorate monohydrate are investigated by means of solid-state NMR spectroscopy, both for static powders and under magic-angle spinning conditions.
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Affiliation(s)
- Diego Carnevale
- Institut des Sciences et Ingénierie Chimiques (ISIC)
- Ecole Polytechnique Fédérale de Lausanne (EPFL)
- CH-1015 Lausanne, Switzerland
| | - Sharon E. Ashbrook
- School of Chemistry
- EaStCHEM and Centre of Magnetic Resonance
- University of St Andrews
- St Andrews, UK
| | - Geoffrey Bodenhausen
- Institut des Sciences et Ingénierie Chimiques (ISIC)
- Ecole Polytechnique Fédérale de Lausanne (EPFL)
- CH-1015 Lausanne, Switzerland
- École Normale Supérieure-PSL Research University
- Département de Chimie
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36
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Goh KSK, Jiménez-Ruiz M, Johnson MR, Rols S, Ollivier J, Denning MS, Mamone S, Levitt MH, Lei X, Li Y, Turro NJ, Murata Y, Horsewill AJ. Symmetry-breaking in the endofullerene H2O@C60 revealed in the quantum dynamics of ortho and para-water: a neutron scattering investigation. Phys Chem Chem Phys 2014; 16:21330-9. [DOI: 10.1039/c4cp03272a] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The splitting of the ortho-H2O ground state is clearly revealed by inelastic neutron scattering.
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Affiliation(s)
- Kelvin S. K. Goh
- School of Physics & Astronomy
- University of Nottingham
- Nottingham NG7 2RD, UK
| | | | | | | | | | - Mark S. Denning
- School of Chemistry
- University of Southampton
- Southampton SO17 1BJ, UK
| | - Salvatore Mamone
- School of Chemistry
- University of Southampton
- Southampton SO17 1BJ, UK
| | - Malcolm H. Levitt
- School of Chemistry
- University of Southampton
- Southampton SO17 1BJ, UK
| | - Xuegong Lei
- Department of Chemistry
- Columbia University
- New York, USA
| | - Yongjun Li
- Department of Chemistry
- Columbia University
- New York, USA
| | | | - Yasujiro Murata
- Institute for Chemical Research
- Kyoto University
- Kyoto 611-0011, Japan
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37
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Ardenkjaer-Larsen JH, Laustsen C, Bowen S, Rizi R. Hyperpolarized H2O MR angiography. Magn Reson Med 2013; 71:50-6. [DOI: 10.1002/mrm.25033] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 10/14/2013] [Accepted: 10/15/2013] [Indexed: 12/29/2022]
Affiliation(s)
- Jan H. Ardenkjaer-Larsen
- Technical University of Denmark; Kgs Lyngby Denmark
- Danish Research Center for Magnetic Resonance; Hvidovre Hospital; Hvidovre Denmark
- GE Healthcare; Broendby Denmark
| | - Christoffer Laustsen
- Danish Research Center for Magnetic Resonance; Hvidovre Hospital; Hvidovre Denmark
- The MR Research Centre; Department of Clinical Medicine; Aarhus University; Aarhus N Denmark
| | - Sean Bowen
- Technical University of Denmark; Kgs Lyngby Denmark
| | - Rahim Rizi
- Department of Radiology; University of Pennsylvania; Philadelphia Pennsylvania USA
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Zhivonitko VV, Kovtunov KV, Chapovsky PL, Koptyug IV. Nuclear Spin Isomers of Ethylene: Enrichment by Chemical Synthesis and Application for NMR Signal Enhancement. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201307389] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Zhivonitko VV, Kovtunov KV, Chapovsky PL, Koptyug IV. Nuclear Spin Isomers of Ethylene: Enrichment by Chemical Synthesis and Application for NMR Signal Enhancement. Angew Chem Int Ed Engl 2013; 52:13251-5. [DOI: 10.1002/anie.201307389] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Indexed: 11/07/2022]
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Tscherbul TV, Grinev TA, Yu HG, Dalgarno A, Kłos J, Alexander MH. Cold collisions of polyatomic molecular radicals with S-state atoms in a magnetic field: An ab initio study of He + CH 2(X̃) collisions. J Chem Phys 2012; 137:104302. [DOI: 10.1063/1.4748258] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Floß J, Grohmann T, Leibscher M, Seideman T. Nuclear spin selective laser control of rotational and torsional dynamics. J Chem Phys 2012; 136:084309. [DOI: 10.1063/1.3687343] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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Bulthuis J, Kresin VV. Beam broadening of polar molecules and clusters in deflection experiments. J Chem Phys 2012; 136:014301. [PMID: 22239775 DOI: 10.1063/1.3673890] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A beam of rotating dipolar particles (molecules or clusters) will broaden when passed through an electric or magnetic field gradient region. This broadening, which is a common experimental observable, can be expressed in terms of the variance of the distribution of the resulting polarization orientation (the direction cosine). Here, the broadening for symmetric-top and linear rotors is discussed. These two types of rotors have qualitatively different low-field orientation distribution functions, but behave similarly in a strong field. While analytical expressions for the polarization variance can be derived from first-order perturbation theory, for experimental guidance it is important to identify the applicability and limitations of these expressions, and the general dependence of the broadening on the experimental parameters. For this purpose, the analytical results are compared with the full diagonalization of the rotational Stark-effect matrices. Conveniently for experimental estimations, it is found that for symmetric tops, the dependence of the broadening parameter on the rotational constant, the axial ratio, and the field strength remains similar to the analytical expression even outside of the perturbative regime. Also, it is observed that the shape envelope, the centroid, and the width of the orientation distribution function for a symmetric top are quite insensitive to the value of its rotational constant (except at low rotational temperatures).
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Affiliation(s)
- J Bulthuis
- Institute for Lasers, Life and Biophotonics, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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Separating water by spin. Nature 2011. [DOI: 10.1038/469447a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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