Photoluminescence of O2 and S2 ions in synthetic sodalities

Photoluminescence spectra of oxygen-doped chloro- and bromosodalites and sulfur-doped chloro-, bromo- and iodosodalites were measured at temperatures between 4.2 and 300 °K. At 4.2 and 77 °K, the emission spectra of oxygen-doped sodalites consisted of a series of peaks in the wavelength range 400–700 nm, with an average energy separation of ∼ 1000 cm^-1. In addition, fine structure, attributed to lattice modes, was observed in each vibrational band. At 4.2 and 77 °K, the sulfur-doped samples showed a multiband spectrum in the 500–750 nm range, with an average separation of ∼ 570 cm^-1 between bands. The spectrum at 4.2 °K exhibited some asymmetry not observed at 77 °K, but no fine structure was resolved. At 300 °K weak, broad-band luminescence was observed from both oxygen- and sulfur-doped samples, with no vibrational structure evident. The results compared very favorably with those reported for oxygen- and sulfur-doped alkali halides, and by analogy the spectra were attributed to luminescence from O^-₂ and S^-₂ molecular ions.