A COMPARATIVE QCISD(T), DFT AND MCSCF STUDY OF THE UNIMOLECULAR, DECOMPOSITION OF THE N-CHLORO-ALPHA-GLYCINE ANION IN GAS-PHASE

Stationary points were localized and characterized on potential energy surfaces for the unimolecular decomposition of the anionic form of N- chloro-alpha-glycine in its singlet and triplet electronic states by m eans of QCISD(T), DFT and MCSCF methods. The present study predicts th at the unimolecular decomposition mechanism takes place in the singlet electronic state through a concerted and slightly asynchronous proces s and the transition structure has an antiperiplanar conformation. A c omparison of the structures for stationary points calculated with diff erent methods yields similar geometries and the components of transiti on vector are weakly dependent on the computing method.