Spin-Forbidden Channels in the Reactions of Unsaturated Hydrocarbons and O(³P)

A number of theoretical and experimental studies indicate that the role of spin-forbidden channels in the reaction of unsaturated hydrocarbons and O(³P) can be important. Branching ratios of the products are sensitive to the chemical structures of the reactants. In our study we use equation-of-motion coupled-cluster methods to investigate electronic structure and to predict the difference in branching ratios for ethylene, propylene, and acetylene. To evaluate one- and two-electron spin-orbit matrix elements we use perturbative approach. All matrix elements are obtained by rotation of the molecules and applying the corresponding Wigner matrices.