Finite-field SCF calculations of the dipole polarisabilities of heavy atoms using relativistic effective potentials

Abstract

The static dipole polarisabilities of Xe, Lu, Hg+, Hg, Tl and At have been determined from finite-field SCF calculations within a valence-electron relativistic effective potential formalism. The effect of the self-consistent inclusion of spin-orbit coupling on the calculated polarisabilities have been investigated by comparing j-averaged (L, Lambda ) results with j-dependent (J, Omega ) calculations. The atoms selected provide a range of closed-shell, particle and hole states for comparative study. The results suggest that self-consistent inclusion of spin-orbit coupling is far more important for the particle states than for the hole states. In the case of Xe, results are presented from calculations using relativistic effective potentials based on both Hamiltonian-consistent and shape-consistent pseudo-orbitals. The shape-consistent approach is found to produce polarisabilities in better agreement with previously determined all-electron Hartree-Fock values. In addition, for Hg the shape-consistent approach yields a polarisability in excellent agreement with all-electron numerical Dirac-Fock calculations.