Spin–orbit coupling and inelastic transitions in collisions of O(1<i>D</i>) with Ar, Kr, and Xe

Abstract

Inelastic collisions of O(1D) with Ar, Kr, and Xe have been treated in the multistate Landau–Zener and the close-coupling approximations. The coupling mechanism is spin–orbit mixing. The dependence of the spin–orbit matrix elements on internuclear distance R is calculated using accurate configuration–interaction wave functions and an effective operator composed of one-electron, one-center terms. The R dependence is found to be very significant. Cross sections for transitions to the individual triplet fine-structure levels, as well as the total inelastic (quenching) cross section, are presented as a function of collision energy. The transitions occur primarily at curve crossings and the quenching rate constants were found to be significantly reduced by centrifugal barriers outside the crossing points. The calculated quenching rate constants at 300 K are (5.4±3.5) ×10−13, (6.0±0.7) ×10−12, and (3.0±0.2) ×10−11 cm3 molecule−1 s−1 for Ar, Kr, and Xe, respectively.