Hylleraas-configuration-interaction nonrelativistic energies for the ~1S ground states of the beryllium isoelectronic sequence

摘要

In a previous work, Sims and Hagstrom ["Hylleraas-configuration-interaction study of the 1 ~1S ground state of neutral beryllium," Phys. Rev. A 83, 032518 (2011)] reported Hylleraasconfiguration- interaction (Hy-CI) method variational calculations for the ~1S ground state of neutral beryllium with an estimated accuracy of a tenth of a microhartree. In this work, the calculations have been extended to higher accuracy and, by simple scaling of the orbital exponents, to the entire Be 2 ~1S isoelectronic sequence. The best nonrelativistic energies for Be, B~+, and C~(++) obtained are ?14.6673 5649 269, ?24.3488 8446 36, and ?36.5348 5236 25 hartree, respectively. Except for Be, all computed nonrelativistic energies are superior to the known reference energies for these states.