Question of mode-specificity in unimolecular reaction dynamics

Abstract

Unimolecular decomposition following state-specific laser excitation is considered. If the transition state for the unimolecular reaction possesses any geometrical symmetry, then it is shown that this can lead to mode-specificity in the decay rates (i.e., different states with essentially the same total energy and angular momentum react at significantly different rates). This is illustrated for a model problem of two coupled oscillators (the Henon–Heiles potential) and also for the unimolecular dissociation of formaldehyde, H2CO→H2