Multiconfiguration Hartree-Fock calculation of photoionization cross sections of the rare gases

A multiconfiguration Hartree-Fock calculation is used to test the hypothesis that ground-state correlations involving excitation of a single of electrons from an outer $p$ shell into $d$ orbitals are the dominant ones in the photoionization cross sections of Ne, Ar, Kr, and Xe. Dramatic improvement in the agreement of dipole length and dipole velocity forms of the cross section is obtaining in going from a Hartree-Fock to a multiconfiguration Hartree-Fock calculation. Results are found to be comparable to recent values obtained using the random-phase approximation with exchange and the $R$ matrix.