Ab initio surface hopping excited-state molecular dynamics approach on the basis of spin–orbit coupled states: An application to the A-band photodissociation of CH3I |
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Authors: | Muneaki Kamiya Tetsuya Taketsugu |
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Institution: | 1. Faculty of Regional Studies, Gifu University, Gifu, 501-1132 Japan;2. Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810 Japan |
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Abstract: | Ab initio molecular dynamics approach has been extended to multi-state dynamics on the basis of the spin–orbit coupled electronic states that are obtained through diagonalization of the spin–orbit coupling matrix with the multi-state second-order multireference perturbation theory energies in diagonal elements and the spin–orbit coupling terms at the state-averaged complete active space self-consistent field level in off-diagonal elements. Nonadiabatic transitions over the spin–orbit coupled states were taken into account explicitly by a surface hopping scheme with utilizing the nonadiabatic coupling terms calculated by numerical differentiation of the spin–orbit coupled wavefunctions and analytical nonadiabatic coupling terms. The present method was applied to the A-band photodissociation of methyl iodide, CH3I + hv → CH3 + I (2P3/2)/I* (2P1/2), for which a pioneering theoretical work was reported by Amatatsu, Yabushita, and Morokuma. The present results reproduced well the experimental branching ratio and energy distributions in the dissociative products. © 2018 Wiley Periodicals, Inc. |
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Keywords: | spin–orbit coupling surface hopping AIMD nonadiabatic coupling photodissociation |
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