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In this paper we extend our previous study (F. Schneider, F. Di Giacomo, and F. A. Gianturco, J. Chem. Phys. 104, 5153) on the topology of the electronic states of the neutral H2O molecule in C2v symmetry by examining the lowest ten potential energy surfaces of the water molecular cation in its doublet states. The relevant electronic energy surfaces of H2O+ are shown as 2D contour maps where possible reaction pathways for several low-lying potential energy surfaces of H2O+ are clearly seen and therefore can be discussed and analyzed in some detail. The present results were obtained using ab initio multireference configuration interaction calculations at 184 nuclear arrangements, as described in our previous paper dealing with the neutral H2O. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We present here computational results on 15 C2v potential energy surfaces (PES) of H2O in its singlet state, while further results on the doublet state of the cation of the same system will be reported in a following paper. The PES are shown as 2D contour maps. Reaction pathways for symmetric dissociation of H2O and photoionisation spectra of H2O are discussed and analyzed in some detail. The results were obtained using ab initio multireference configuration interaction (MRDCI) calculations at 184 nuclear arrangements and should provide one of the most extensive analysis of the electronic features of this very important chemical system. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]