Abstract
A simple procedure is described for calculating spin‐orbit and nonadiabatic interactions by an extension of the diatomics‐in‐molecules approach. The method can be easily applied to a large number of polyatomic systems and will hopefully be of value in obtaining qualitative and quantitative descriptions of many important molecular collision processes which involve more than one potential energy surface. Results are presented for two such processes, the quenching of Li(2 2P) by H2 and the reaction of F atoms with H2.