Emission Spectra of S2−, Se2−, and SeS− Ions in KI Crystals

Luminescence emission measurements made at 4.2°K on KI crystals containing the ions S₂⁻, Se₂⁻, and SeS⁻ revealed characteristic banded emission spectra similar to that of O₂⁻, though both emission and excitation occur at longer wavelengths. The SeS⁻ emission was always accompanied by S₂⁻ and Se₂⁻ emissions, so the emission spectrum was computed from three spectra obtained by excitation wavelengths favoring S₂⁻, SeS⁻, and Se₂⁻ emission, respectively. From the detailed isotopic structure observed in all emission spectra, the ground‐state vibration constants ${\omega }_e″$ and ${\omega }_e{\mathrm{″x}}_e″$ were calculated, and also values of ${\nu }_{00}$ , the origin of the vibrational band system.