Date of this Version
Ab initio theoretical calculations are presented for the cross section, photoelectron angular distribution, and photoelectron spin polarization resulting from photoionization of the 6s electron of cesium. Starting from an initial basis of nonrelativistic Hartree-Fock wave functions, the effect of final-state spin-orbit interaction in the Breit-Pauli approximation is treated exactly. The effect of core relaxation is also examined. Our calculated results agree with recent experimental measurements of the photoionization cross section and the photoelectron spin polarization. Comparison is made with other theoretical calculations. Finally, the length form of the electric dipole interaction operator is shown to be consistent with gauge invariance when one solves for the exact eigenstates of a Hamiltonian containing spin-orbit interactions.