Product fine-structure resolved photodissociation dynamics: The A band of H2O

The photodissociation dynamics of H2O in its first absorption band is investigated on an accurate potential energy surface based on a large number of high-level ab initio points. Several rovibrational states of the parent molecule are considered. Different from most previous theoretical studies, the spin-orbit and Lambda-doublet populations of the open-shell OH fragment are reported from full-dimensional wave packet calculations. The populations of the two spin-orbit manifolds are in most cases close to the statistical limit, but the Lambda-doublet is dominated by the A '' component, thanks largely to the fast in-plane dissociation of H2O((A) over tilde (1)A ''). Comparisons with experimental data and a Franck-Condon model are generally very good, although some discrepancies exist. (C) 2014 AIP Publishing LLC.