A CSF-based multi-reference coupled pair approximation

Abstract

Using the newly developed multi-reference coupled pair approximation program code, the adiabatic potential curves of the ground states of F2, As2 and As2+ were calculated. Computed spectroscopic constants of these molecules were found to be in good agreement with experimental values. The resulting binding energy of As2 (3.86 eV) was compared with the experimental value of 3.99 eV [15] and the best multi-reference configuration interaction value (3.58 eV) reported previously by the present authors. The calculated first adiabatic ionization potential of As2 (9.67 eV) was found to be in good agreement with the experimental result.