Nonadiabatic coupling and diabatic electronic population dynamics on 11A2 and 11B1 states of ozone molecule

Abstract

AbstractIn this work, we examine nonadiabatic population dynamics for 11B1 and 11A2 states of ozone molecule (O3). In O3, two lowest singlet excited states, 1A2 and 1B1, can be coupled. Thus, population transfer between them occurs through the seam involving these two states. At any point of the seam (conical intersection), the Born‐Oppenheimer approximation breaks down, and it is necessary to investigate nonadiabatic dynamics. We consider a linear vibronic coupling Hamiltonian model and evaluate vibronic coupling constant, diabatic frequencies for three modes of O3, bilinear and quadratic coupling constants for diabatic potentials, displacements, and Huang‐Rhys coupling constants using ab initio calculations. The electronic structure calculations have been performed at the multireference configuration interaction and complete active space with second‐order perturbation theory with a full‐valence complete active space self‐consistent field methods and augmented Dunning's standard correlation‐consistent‐polarized quadruple zeta basis set to determine ab initio potential energy surfaces for the ground state and first two excited states of O3, respectively. We have chosen active space comprising 18 electrons distributed over 12 active orbitals. Our calculations predict the linear vibronic coupling constant 0.123 eV. We have obtained the population on the 11B1 and 11A2 excited electronic states for the first 500 fs after photoexcitation.