Photoluminescence and excitation spectroscopy of rare gases

The photoluminescence bands of solid rare gases are discussed. The excitation spectra of the bands measured on samples with a “clean” surface show that the bulk quantum efficiency is independent of excitation energy in the region of excitonic excitation. Contamination leads to surface recombination and serves as a sink for excitons. Therefore the dynamics of free excitons can be studied from excitation spectra. Diffusive motion is assumed. Values for the diffusion lengths are deduced.