Rotational and spin-orbit effects in the dynamics of O(P-3(j))+hydrocarbon reactions .2. Models for spin-orbit propensities

The spin-orbit states of OH have been found in part I to be unequally populated in reactions of O(P-3(j)) with saturated hydrocarbons. We clarify the correlations in these systems within an adiabatic, Omega-conserving approximation, and show that the observed OH spin-orbit distributions are not well reproduced in this adiabatic limit. However, the inclusion of strong nonadiabatic coupling between surfaces of the same Omega and parity results in a much improved prediction. The necessary mixing is demonstrated to be compatible with a previous independent characterization of the entrance channel surfaces in O(P-3(j)) + CH4 collisions, and with the known propensities for inelastic, j-changing collisions of O(P-3(j)) with closed shell partners. The nonadiabatic model which agrees best with the observed OH spin-orbit ratios suggests that the O(P-3(j)) reactivity should vary only moderately with j. (C) 1997 American Institute of Physics.