On some structural properties of various electronic states of the hydroxonium ion

Abstract

Calculations have been carried out for several excited electronic states of the protonated water molecule the hydroxonium ion H3O+ at the level of highly correlated, multireference double-excitation configuration-interaction (MRD-CI) computations for several potential energy profiles of the system. It was found that different structural geometries exist for the ground and for the excited electronic states and that such geometries are very helpful for a quantitative interpretation of previous mass spectrometric fragmentation patterns. The general features of the umbrella motion in several electronic states are described for the title system and their importance for the analysis of the above spectra is shown for the first time. The possible extension of the present study to analyze charge-exchange and direct inelastic collision experiments in molecular beams is briefly outlined.