Double-linked Hylleraas configuration-interaction calculation for the nonrelativistic ground-state energy of the Be atom.

Abstract

High-precision variational calculations using multiple basis sets in Hylleraas coordinates are presented for the 1${\mathit{s}}^{2}$2${\mathit{s}}^{2}$ $^{1}$${\mathit{S}}_{0}$ state of beryllium. The variational bound of -14.667 350(8) a.u. for the nonrelativistic ground-state energy in the infinite-mass approximation is in good agreement with values obtained by conventional configuration-interaction calculations.