MOLECULAR SCHRODINGER EQUATION .X. POTENTIAL SURFACES FOR GROUND AND EXCITED STATES OF ISOSCELES H3++ AND H3+

Accurate potential-energy surfaces are reported for the ground states, and for several excited states, of the isosceles triangular configurations of the molecular ions H32+ and H3+. The ground states are 2A1 and 1A1, respectively, of group C2v, and these include the σg linear symmetric forms and the Ai states of the equilateral D3h triangles. The four excited-state surfaces are 2B1 and 2B2 for H32+, as well as 1B1 and 1B2 for H3 +; these include the IIu and ∑u states of the linear D∞h ions and the A2″' and E′ states of the D3h ions. These excited states are of possible interest in connection with ultraviolet spectroscopic studies of H3 +, long known from mass spectrometry to be a stable species. Each of the six surfaces is given in analytic form, and as an energy contour map. The two-electron wavefunctions used are basically of the configuration type, with an extensive additional treatment of electron correlation. In all cases the required matrices were computed with the new Diophantine integration scheme, which supercedes the now obsolete Monte Carlo method employed in our earlier papers on H3+.