RAMAN SPECTRA OF NEGATIVE MOLECULAR IONS DOPED IN ALKALI HALIDE CRYSTALS

Raman bands arising from S2- and S3- have been observed in alkali halide single crystals which had been heated in the presence of sulphur vapor. The S3- ion could also be detected in the mineral ultramarine. Since the excitation frequency was sometimes close to the absorption band of these species, a resonance Raman effect was observed. This was strongest for the S3- species in KCl where the fifth overtone of the symmetrical stretching mode vibrational could be seen. In similarly treated crystals, the vibrational Raman bands of Se2- and SeS- were observed. Raman data for N2- in potassium halide single crystals are also reported. © 1969.