Halogen Migration in the Photofragmentation of Halothane.

The photofragmentation of halothane (CF(3)CHBrCl) was studied with synchrotron radiation by photoionization efficiency (PIE) measurements and photoelectron-photoion coincidence (PEPICO) experiments, as well as by a theoretical exploration of potential energy surfaces. Among the other fragments, the formation of the CHClF(+) and CHBrF(+) ions, which involves the transfer of a F atom between the two moieties of the parent molecule, was observed. To understand the mechanisms leading to the halogen migration, a detailed theoretical study of the production of CHClF(+), m/z 67(+), based on DFT calculations and natural bond orbital (NBO) analysis was conducted. The results contribute to the understanding of the photochemistry of halothane, its polluting behavior in the high atmosphere, and the formation of highly reactive species.