Radiative Annihilations of Excitons in Solid Rare Gases

Emission spectra of Ar-Xe solid solutions have studied. At small xenon concentration, a band called M , is observed in addition to an intrinsic luminescence of the pure argon crystal. With increasing the doped xenon concentration, another doublet bands, called D 1 and D 2 , are found to appear. Excitation spectra for these emissions reveal that the M and D 's bands are attributed to the xenon monomer and dimer in argon lattice, respectively. With further increase of the xenon doping, the D 1 band-peak approaches that of the intrinsic luminescence of the pure xenon crystal. From this fact the intrinsic luminescence of the pure xenon crystal has been considered to arise from a relaxed exciton of a diatomic molecular type.