Vacuum-ultraviolet fluorescence under monochromatic excitation and collision processes in gaseous Kr and Xe

Abstract

The vacuum-ultraviolet fluorescence of Kr and Xe and its dependence on gas pressure (10 to 500 Torr) was studied under monochromatic excitation in the vicinity of the first ( 3 P 1 ) and second ( 1 P 1 ) resonance states. For excitation synchrotron radiation was used. Excitation in the long-wavelength wing of the 3 P 1 states directly results in excited molecules (e.g. 2Kr+h(cross) omega to Kr 2 *). The radiative decay of these molecules results in the first (Kr: 1250 AA, Xe: 1500 AA) and second (Kr: 1470 AA, Xe: 1700 AA) continua. Under resonant 3 P 1 excitation, molecule formation via three-body collisions (e.g. Kr*+2Kr to Kr 2 *+Kr) is established. Excitation of 1 P 1 states results in 1 P 1 emission and the continua. The 1 P 1 emission contains molecular components. In Xe, it is strongly quenched by collisional interaction between the 1 P 1 state and a near-lying atomic p state.