VIBRONIC COUPLING EFFECTS IN THE OZONE CATION

A multi-mode vibronic coupling Hamiltonian which includes coupling terms up to second order in the nuclear displacements is used to study theoretically the vibronic interactions between the ground and first excited electronic states of the ozone cation, O3+. The relevant coupling constants rely on previous large-scale CASSCF and MRCI calculations which already identified a low-lying conical inter-section between the potential energy surfaces of these states. Good agreement of the calculated intensity distribution with the peculiar shape of the experimental photoelectron spectrum is achieved. The results unambiguously demonstrate the importance of vibronic interactions in O3+. They further underline their ubiquitous role as a basic dynamic mechanism even in small polyatomic molecules.