An ab initio study of the low-lying electronic excited states of CH 3OBr

Abstract

Using high level ab initio molecular orbital methods, theoretical studies were performed on the low-lying excited states of CH 3OBr. The complete active space self-consistent field (CASSCF) and multi-reference configuration interaction (MRCI) methods, with the cc-pVTZ basis set, were used to calculate the vertical excitation energies for the lowest three 1 A ′ , two 1 A″ , two 3 A ′ , and two 3 A″ states. The CASSCF method was used to obtain the potential energy curves for the lowest three 1 A ′ , two 1 A″ , two 3 A ′ , and two 3 A″ states of CH 3OBr along the O–Br coordinate. All of the eight excited states were found to be strongly repulsive along the O–Br coordinate.