TWO-PHOTON LASER-ASSISTED REACTIONS OF Xe WITH HALOGEN CONTAINING MOLECULES

Abstract
The two-photon, laser-assisted reactions between Xe (or Kr) and several halogen containing molecules have been observed by focusing the output of a pulsed dye-laser into dilute gas mixtures of Xe and the reagent. The occurrence of the reaction is detected from the B-X fluorescence of the XeCl*, XeBr* and XeI* products. Results from studies with SOCl₂, CCl₄, CCl₃Br, CCl₂Br₂, Br₂ and I₂ are emphasized. In some instances the utilization of laser pulses of different frequency to drive the reaction enhanced the two-photon cross section, relative to one-color experiments, because of a more favorable energy resonance with the one-photon RX* intermediate state. Direct excitation from bound and free Xe/RX pairs on the van der Waals potential to the ion-pair, Xe⁺RX^-, reactive potential explains most aspects of these laser-assisted reactions. One application of these laser-assisted reactions is as a very rapid generation source for XeCl* and KrF* molecules in order to study their quenching and relaxation kinetics.