Observation of surface-sensitive luminescence in solid argon; relation to self-trapping and relaxation of excitons

The luminescent emission of solid argon was measured under state-selective excitation using synchrotron radiation. With the aid of excitation spectra and surface coverage experiments it was possible to show that the higher-energy emission bands at 1090 and at 1067 AA are produced by centres located at the surface of the sample. The interpretation was confirmed by time-resolved measurements and theoretical considerations relative to (i) vibrational relaxation rates and (ii) the effect of the dimensionality on the stability of an exciton in a deformable lattice.