APPROXIMATELY PROJECTED UHF MOLLER-PLESSET CALCULATIONS OF THE POTENTIAL-ENERGY PROFILES FOR THE REACTION OF THE TRIPLET OXYGEN ATOM WITH ETHYLENE

Geometries for the CH2CH2O diradical, both singlet and triplet, in various conformations were optimized and the unimolecular reaction paths for the lowest-lying singlet and triplet diradicals were determined by the SCF energy gradient method employing the 6-31G* basis functions. Approximately projected UHF Møller-Plesset calculations were then carried out for the relevant transition state structures, key intermediates and fragmentation products. It is found that both channel (1) leading to CH3 + HCO through the singlet (1A′) CH2CH2O diradical and channel (2) giving rise to CH2CHO + H through the triplet (3A″) diradical are energetically acceptable. The branching ratio between these processes should be dependent on the rate of the intersystem crossing between the 1A′ and 3A″ states. © 1990.