Atomic polarisabilities and polarised pseudostates in the multiconfigurational approach. III. Second-row atoms and ions

Abstract

For pt.II see ibid., vol.10, no.6, p.1015 (1977). Mean static dipole polarisabilities are calculated for the ground states of neutral atoms from Al to Cl and for singly ionised Si+ to Ar+. The polarisability is expressed in terms of the first-order correction in the wavefunction (due to the static electric dipole perturbation) which is determined variationally as a configuration interaction expansion. Near-degeneracy effects are included. The results are comparable with those obtained from the coupled Hartree-Fock scheme. The first-order wavefunctions may be used as target pseudostates in electron-atom scattering.