Argon, krypton, and xenon excimer luminescence: From the dilute gas to the condensed phase

Abstract

For the first time, the evolution of luminescence from rare gases was studied as a function of number density. Synchrotron radiation served as a light source for selective and pulsed excitation of the samples. The excitation spectra confirm previous results on perturbed Rydberg states and exciton appearance in dense media. In time-resolved emission spectra the peak energies and widths of the luminescence bands were followed. The energy separation between the fast and slow components is found to be density independent. A model proposed by Cheshnovsky et al. [Chem. Phys. Lett. 15, 475 (1972)] accounts for the change in peak width with temperature. Both lifetimes decrease with increasing density. The data extrapolate to 3.3±0.1 ns (Ar); 3.4±0.1 ns, 270±5 ns (Kr); 4.5±0.1 ns, 100±5 ns (Xe) for the low density limit. For the solid at the triple point, we obtain 1.3±0.1 ns, 82±5 ns (Kr) and 1.1±0.1 ns, 18.5±0.5 ns (Xe). Theories on density dependence of lifetimes give only a qualitative description of the experimental results.