AB INITIO POTENTIAL ENERGY SURFACES OF $H_{4}{^{+}}$

Abstract

Potential energy surfaces for the ground and excited states of $H_{2}-H_{2}{^{+}}$ have been calculated using SCF and limited CI techniques. Several orientations have been studied, with the $H_{2}$ and $H_{2}^{+}$ bond lengths restricted to their equilibrium values. A basis set of 28 symmetry-adapted Gaussian-type orbital was employed in the SCF and CI calculations. Perturbation techniques have been applied to the study of the asymptotic limits for the two states, Results show an interaction energy of approximately 1.6 eV for the ground state of the most stable geometry -- a perpendicular orientation with the $H_{2}{^{+}}$ molecule lying along the $C_{2}$ symmetry axis. All of the lowest electronically excited states were found to be repulsive. These ground and excited-state energy surfaces will be used in multistate-impact-para-meter calculations of the cross-sections for charge transfer reactions between $H_{2}$ and $H_{2}{^{+}}$.