Formation of an S₂ ^- Molecular Ion and Its Luminescence Characteristics in KCl:MnS Crystals

Abstract

It was found that when a KCl crystal doubly doped with a trace of MnS was irradiated with UV light, the S 2 - molecular ions were effectively produced through a photochemical reaction. These S 2 - molecular ions exhibited characteristic vibronic luminescence composed of zero-phonon lines and phonon-side bands below 160 K. Such a vibronic structure related to zero-phonon lines could also be observed for the first time in the luminescence excitation band. From the analysis of the spectral positions of zero-phonon lines in the emission and excitation spectra, the average vibrational frequencies of the S 2 - molecular ion in the ground state and excited state were determined to be 1.78×10 13 s -1 and 1.13×10 13 s -1 respectively.