The static dipole polarisability of calcium; a treatment including core-valence and core correlation effects

Abstract

The static dipole polarisability of the ground state of calcium is calculated. 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. The theoretical values of Reinsch and Meyer (1976) indicate a substantial drop in the polarisability due to core effects, whereas the results reported suggest that core or core-valence effects are much smaller. The author has also shown that quite an accurate value for the polarisability can be obtained using truncated expansions for the wavefunction compositions. A new experimental value for the dipole polarisability of calcium with smaller error bars would be valuable in the development of theoretical calculations of atomic polarisabilities.