A b i n i t i o effective core potentials including relativistic effects. II. Potential energy curves for Xe2, Xe+2, and Xe*2

Abstract

Potential energy curves for the ground ¹Σ⁺_g state of Xe₂, the first four states of the Xe⁺₂ ions, and the eight Xe*₂ excimer states corresponding to the addition of a 6sσ_g Rydberg electron to these ion cores have been computed using averaged relativistic effective core potentials (AREP) and the self‐consistent field approximation for the valence electrons. The calculations were carried out using the LS‐coupling scheme with the effects of spin–orbit coupling included in the resulting potential energy curves using an empirical procedure. A comparison of nonrelativistic and averaged relativistic EP’s and subsequent molecular calculations indicates that relativistic effects arising from the mass–velocity and Darwin terms are not important for these properties of Xe₂ molecules. Spectroscopic constants for Xe⁺₂ are in good agreement with all electron CI calculations suggesting that the computed values for Xe*₂ excimers should be reliable. The lifetime for the O_u⁺ state of the Xe₂* is computed to be 5.6 nsec which is in the range of the experimentally determined values.