Electronically nonadiabatic mechanism of the vibrational relaxation of NO in Ar: Rate coefficients from ab initio potentials and asymptotic coupling
| Autor: | E. I. Dashevskaya, Evgeni E. Nikitin, I. Litvin, J. Troe |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Coupling Ab initio General Physics and Astronomy 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Potential energy 0104 chemical sciences Reaction coordinate Vibronic coupling Ab initio quantum chemistry methods Vibrational energy relaxation Physics::Chemical Physics Physical and Theoretical Chemistry Atomic physics 0210 nano-technology Adiabatic process |
| Zdroj: | The Journal of chemical physics. 149(1) |
| ISSN: | 1089-7690 |
| Popis: | In this paper, the electronically nonadiabatic Landau-Zener (LZ) mechanism for the vibrational relaxation v = 1 → v = 0 of NO(X2Π) in collisions with Ar(S01) is discussed. It corresponds to nonadiabatic transitions between two crossing vibronic potential energy surfaces (PESs) originating from vibrational states of the collision complex and supported by two coupled electronic PESs. The LZ rate coefficients k10LZ are calculated within the uniform Airy approach in the reaction coordinate approximation with parameters derived from ab initio PESs and an asymptotic estimation of the Franck-Condon factor in the nonadiabatic coupling region. The rate coefficients are close to the experimental rate coefficients available over the range of 900-2500 K, where the electronically adiabatic Landau-Teller (LT) mechanism with the rate coefficients k10LT does not make a noticeable contribution to the total relaxation rate. The ratio k10LZ/k10LT increases with temperature and the LZ and LT mechanisms have comparable rates at about 4000 K. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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