A b i n i t i o MC–SCF ground-state potential energy curves for LiH−, NaH−, and CsH−

Abstract

We have evaluated the ¹Σ⁺ ground states of LiH, NaH, and CsH and the ²Σ⁺ ground states of LiH⁻, NaH⁻, and CsH⁻, as well as the ²Σ⁺ ground state of CsH⁺, over a wide range of internuclear distances. Multiconfiguration‐self‐consistent‐field wavefunctions were obtained with the optimized valence configuration approach to the description of chemical bonding. Four configurations for the neutral molecules and seven for the negative ions provided satisfactory descriptions. All of the negative‐molecular‐ion ground states are attractive and have lower potential energies than the neutral‐parent‐hydride molecules over the internuclear distances studied. Molecular electron affinities at the equilibrium internuclear separations were found to be 0.283 eV (LiH), 0.278 eV (NaH), and 0.357 eV (CsH).