THE LINEAR SYMMETRICAL STATES OF WATER AND OF ITS CATION

The potential energy curves of several electronic states of linear sym metric water molecules (singlets and doublets) and the positive water ion have been calculated with the multireference double-excitation con figuration-interaction (MRDCI) method. Using a saturated basis set inc luding f- and g- functions and diffuse orbitals, a number of atomic st ates of oxygen and its cation as well as of the oxygen anion were also determined. The analysis of the results obtained shows interesting co rrelations between the sudden fragmentation of these excited species a nd the many possible asymptotic atomic and molecular, excited and de-e xcited, fragments which can be formed during the break-up of both the neutral and ionic species in this specific geometry. The relevance of these results for the study of relative dynamical stabilities of ionic clusters containing water is analysed in our final discussion.