He–Be 2+ interaction energy at small internuclear distances

The He–Be2+ interaction energy for internuclear separations from 0.16 to 0.79 Å has been determined from single-configuration MO-SCF calculations and compared to that deduced by Giffen and Berry from scattering data. The ratio of the calculated to experimental energies varies from 1.45 at 0.16 Å to 1.03 at 0.79 Å. The large discrepancy between theory and experiment for small internuclear separations is similar to that found by Giffen and Berry from a Thomas-Fermi-Dirac calculation of the interaction energy. The MO-SCF interaction is represented to within 10% by a Born-Mayer potential V(R)= 944 exp(−6.23 R) eV with R in angstroms.