Production of rare gas-halide excimers following trimer absorption at ultraviolet wavelengths

Abstract

Absorption by the rare gas-halide trimers Kr{sub 2}F(4{sup 2}{Gamma}) and Xe{sub 2}Cl(4{sup 2}{Gamma}) has been shown to result in the immediate formation of the respective excimer, KrF(B,C) or XeCl(B,C), and the branching ratio for this process has been measured at several ultraviolet wavelengths. In experiments using excimer lasers as both pump and probe, the branching ratio for both trimers has been found to be 0.9 {plus minus} 0.1 for wavelengths above 300 nm and approximately zero at wavelengths shorter than 250 nm. These results suggest that the trimers have strongly repulsive potential energy curves that terminate on the excimer levels. This is not predicted by theoretical modeling and demonstrates the need for improvement in the theoretical understanding of the trimers and perhaps even the excimers.