Convergence studies of atomic properties from variational methods: total energy, ionization energy, specific mass shift, and hyperfine parameters for Li

Abstract

Systematic variational calculations using the multi-configuration Hartree-Fock method for Li are reported. For 1s22s 2S of Li, an nl-expansion is attempted in configuration space, similar to a partial wave expansion for helium-like systems. The total energy, ionization energy, specific mass shift, and hyperfine contact term are calculated with respect to increasing size of the configuration set. A comparison is made with n-expansion in configuration space, which is found to be the more efficient method. The total energy obtained from our variational procedure is lower than that of a previously reported partial wave study on ground state of Li. Similar n-expansion studies are performed for 1s22p 2P. For the latter, the 2s-2p transition integrals are reported, showing convergence of the transition energy as well as the length and velocity form of the f-value.