Ab Initio Studies on BeH+ (X1Σ+)

Abstract

A 38‐configuration wavefunction was calculated for ${\mathrm{BeH}}^{+}{\mathrm{(X}}^1{\Sigma }^{+})$ at $\text{R\hspace{0.17em}=\hspace{0.17em}2.48}\mathrm{bohr}$ , the experimental equilibrium $R$ distance, to give an energy of − 14.92196 hartree and an electric moment of 1.578 a.u. This function gave 79% of the binding energy and 73% of the correlation energy. Comparative studies were made with the important zeroth‐order configurations, ${\mathrm{Be}}^{+}{(}^2\mathrm{S)}\mathrm{H}{(}^2\mathrm{S),}{\mathrm{Be}}^{+}{(}^2\mathrm{P)}\mathrm{H}{(}^2\mathrm{S),}{\mathrm{Be}}^{\text{2+}}{(}^1\mathrm{S)}{\mathrm{H}}^{-}{(}^1\mathrm{S),\; and}\mathrm{Be}{(}^1\mathrm{S)}{\mathrm{H}}^{+}$ , and with previous work on the $\mathrm{LiH}{\mathrm{(X}}^1{\Sigma }^{+})$ molecule. The polar nature of BeH⁺ appears to be best described in terms of a valence‐bond picture, where ${\text{(2s–2p}}_{\mathrm{gu}})$ hybridization amply explains the charge transfer.