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Condensed-phase isomerization through tunnelling gateways
- Quantum mechanical tunnelling describes transmission of matter waves through a barrier with height larger than the energy of the wave(1). Tunnelling becomes important when the de Broglie wavelength of the particle exceeds the barrier thickness; because wavelength increases with decreasing mass, lighter particles tunnel more efficiently than heavier ones. However, there exist examples in condensed-phase chemistry where increasing mass leads to increased tunnelling rates(2). In contrast to the textbook approach, which considers transitions between continuum states, condensed-phase reactions involve transitions between bound states of reactants and products. Here this conceptual distinction is highlighted by experimental measurements of isotopologue-specific tunnelling rates for CO rotational isomerization at an NaCl surface(3,4), showing nonmonotonic mass dependence. A quantum rate theory of isomerization is developed wherein transitions between sub-barrier reactant and product states occur through interaction with the environment.Quantum mechanical tunnelling describes transmission of matter waves through a barrier with height larger than the energy of the wave(1). Tunnelling becomes important when the de Broglie wavelength of the particle exceeds the barrier thickness; because wavelength increases with decreasing mass, lighter particles tunnel more efficiently than heavier ones. However, there exist examples in condensed-phase chemistry where increasing mass leads to increased tunnelling rates(2). In contrast to the textbook approach, which considers transitions between continuum states, condensed-phase reactions involve transitions between bound states of reactants and products. Here this conceptual distinction is highlighted by experimental measurements of isotopologue-specific tunnelling rates for CO rotational isomerization at an NaCl surface(3,4), showing nonmonotonic mass dependence. A quantum rate theory of isomerization is developed wherein transitions between sub-barrier reactant and product states occur through interaction with the environment. Tunnelling is fastest for specific pairs of states (gateways), the quantum mechanical details of which lead to enhanced cross-barrier coupling; the energies of these gateways arise nonsystematically, giving an erratic mass dependence. Gateways also accelerate ground-state isomerization, acting as leaky holes through the reaction barrier. This simple model provides a way to account for tunnelling in condensed-phase chemistry, and indicates that heavy-atom tunnelling may be more important than typically assumed.…
Author details: | Arnab ChoudhuryORCiD, Jessalyn A. A. DeVine, Shreya SinhaORCiD, Jascha Alexander LauORCiDGND, Alexander KandratsenkaORCiD, Dirk SchwarzerORCiD, Peter SaalfrankORCiDGND, Alec Michael WodtkeORCiDGND |
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DOI: | https://doi.org/10.1038/s41586-022-05451-0 |
ISSN: | 0028-0836 |
ISSN: | 1476-4687 |
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/36265512 |
Title of parent work (English): | Nature : the international weekly journal of science |
Publisher: | Macmillan Publishers Limited, part of Springer Nature |
Place of publishing: | London |
Publication type: | Article |
Language: | English |
Date of first publication: | 2022/10/20 |
Publication year: | 2022 |
Release date: | 2023/11/01 |
Volume: | 612 |
Issue: | 7941 |
Number of pages: | 6 |
First page: | 691 |
Last Page: | 695 |
Funding institution: | Alexander von Humboldt Foundation; Deutsche Forschungsgemeinschaft [Sa; 548/18-1]; International Max Planck Research School for Elementary; Processes in Physical Chemistry |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 50 Naturwissenschaften / 500 Naturwissenschaften und Mathematik |
Peer review: | Referiert |
Publishing method: | Open Access / Hybrid Open-Access |
License (German): | CC-BY - Namensnennung 4.0 International |