Coupled Multiconfigurational Self-Consistent-Field Method for Atomic Dipole Polarizabilities. I. Theory and Application to Carbon

A method for calculating static dipole polarizabilities of atoms within a multiconfigurational self-consistent-field (SCF) framework is presented. The method involves the direct solution of the multiconfigurational SCF equations of an atom in the presence of a perturbing field which is simulated by a charged particle. The use of a multiconfigurational framework allows this technique to be applied straightforwardly to any given state of both degenerate and nondegenerate atoms, and also allows the explicit introduction of correlation effects. Sample calculations are reported for the static dipole polarizabilities of the carbon atom in its ${}_{}{}^1{}_{}{}^{}S$, ${}_{}{}^1{}_{}{}^{}D$, and ${}_{}{}^3{}_{}{}^{}P$ states with partial inclusion of correlation. The results are compared with those obtained from many-body perturbation theory, and other techniques. In addition, a prescription for specifying a sufficiently flexible set of polarization basis functions is described.