An Experimental and Theoretical Study of the Spin–Orbit Interaction for CO+(A 2Π3/2,1/2, v+=0–41) and O+2(X 2Π3/2,1/2g, v+=0–38)

Accurate spin–orbit splitting constants (Av+) for the vibrational levels v+=0–41 of CO+(A 2Π3/2,1/2) have been determined in a rotationally resolved pulsed field ionization photoelectron study. A change in slope is observed in the v+ dependence for Av+ at v+≈19–20. This observation is attributed to perturbation of the CO+(A 2Π) potential by the CO+(B 2Σ+) state. Theoretical Av+ values for CO+(A 2Π3/2,1/2, v+=0–41) have also been obtained using a newly developed ab initio computational routine for spin–orbit coupling calculations. The theoretical Av+ predictions computed using this routine are found to be in agreement with the experimental Av+ values for CO+(A 2Π3/2,1/2, v+=0–41). Similar Av+calculations obtained for O+2(X 2Π3/2,1/2g, v+=0–38) are also in accord with the recent experimental Av+ values reported by Song et al. [ J. Chem. Phys. 111, 1905 (1999)].