CL 2P-PHOTOELECTRON SPECTRUM OF HCL STUDIED BY FULLY RELATIVISTIC, SELF-CONSISTENT-FIELD, AND CONFIGURATION-INTERACTION CALCULATIONS

Fully relativistic, all-electron self-consistent-held calculations, ba sed on the Dirac-Coulomb(-Gaunt) Hamiltonian, have been performed on t he ground state and the three Cl 2p-ionized states of HCl. The calcula tions are done by the Dirac-Fock method and correlation is included th rough relativistic configuration-interaction calculations. The core-or bitals of HCl are shown to have a relativistic character and a descrip tion of the Cl 2p-ionized states in terms of omega omega-coupling is f ound to be crucial. Calculated Cl 2p-ionization energies and energy sp littings are in very good agreement with recent experimental, high res olution results. For the ionization energies, relaxation dominates cor relation, and the effect of correlation are found to be neglible. Furt hermore, the combined effects of the Gaunt term and core-valence corre lation brings the calculated energy splittings in excellent agreement with experiment.