Model for calculating spin-orbit interactions with applications to photoelectron spectroscopy

Abstract

A semiempirical model has been developed for estimating spin-orbit interactions in molecular ion states derived by ionization of closed-shell neutral molecule states. A perturbation approach is used with an effective spin-orbit interaction operator Hso and approximate Mulliken-Wolfsberg-Helmholz molecular orbital (MO) wavefunctions. Effective spin-orbit parameters ζv were obtained by interpolation with respect to atomic charges derived from the MO calculations. The He I photoelectron spectra of the PX3(X = Cl, Br, I) and PYX3(X = Cl, Br; Y = O, S) series have been measured. Splittings observed in some of the ionization bands of this series have been successfully interpretated as spin-orbit splittings using the newly developed model.