Relativistic and nonrelativistic effective core potentials for xenon. Applications to XeF, Xe2, and Xe2+

Abstract

Valence electron calculations on the low-lying electronic states of XeF, Xe2, and Xe2+ are reported using recently developed nonrelativistic and relativistic effective core potentials. The results indicate that apart from spin–orbit coupling relativistic effects are negligible for xenon. Comparison with previous all-electron calculations reveals that the valence electron dissociation and transition energies agree to 0.1 eV or better with all-electron results. The errors in the calculated values for Re are slightly greater (0.05 Å for XeF and 0.1 Å for Xe+2). The valence electron calculations generally appear to underestimate repulsive two-center interactions leading to significant errors at small internuclear separations in the repulsive wall of the potential curves. Comparison with the valence electron results of Lee, Ermler, Pitzer, and Winter shows excellent agreement, indicating that the simple, approximate approach used here for including relativistic effects in the effective core potential is valid.