Non-Born–Oppenheimer study of positronic molecular systems: e¿LiH

Abstract

Very accurate non-Born–Oppenheimer variational calculations of the ground state of e1LiH have been performed using explicitly correlated Gaussian functions with preexponential factors dependent on powers of the internuclear distance. In order to determine the positron detachment energy of e1LiH and the dissociation energy corresponding to the e1LiH fragmentation into HPs and Li1 we also calculated non-BO energies of HPs, LiH, and Li1. For all the systems the calculations provided the lowest ever-reported variational upper-bounds to the ground state energies. Annihilation rates of HPs and e1LiH were also computed. The dissociation energy of e1LiH into HPs and Li1 was determined to be 0.036 548 hartree