Spectrum of the negative Be ion

Abstract

The existence of ${\mathrm{Be}}^{\ensuremath{-}}$ is established from electron correlation calculations which include one-, two-, three-, and four-orbital excitations. The discrete spectrum of ${\mathrm{Be}}^{\ensuremath{-}}$ consists of three states: $1{s}^{2}2s2{p}^{2} ^{4}P$, $1{s}^{2}2{p}^{3} ^{4}S^{o}$, and $1s2s2{p}^{3} ^{6}S^{o}$. The $^{4}S^{o}\ensuremath{-}^{4}P$ transition offers the possibility of experimental detection of ${\mathrm{Be}}^{\ensuremath{-}}$, e.g., by beam-foil methods. The theoretical wavelength and probability for the transition are $\ensuremath{\lambda}=2671$ \AA{} and $A=0.67\ifmmode\times\else\texttimes\fi{}{10}^{9}$ ${\mathrm{sec}}^{\ensuremath{-}1}$, respectively.