Radiation defects in sulfates of alkali and alkaline-earth metals creating at excitation by ultraviolet photons

Abstract

X-ray luminescence, photoluminescence, and vacuum ultraviolet spectroscopy have been used to study the nature of intrinsic luminescence and the formation of electron-hole trapping centers in a LiNaSO4 crystal in a broad spectral range at a temperature of 15-300 K. Based on the measurement of the spectrum of creation of intrinsic luminescence and recombination radiation at electron-hole trapping centers, the minimum energy of creation of electron-hole pairs is estimated, which determines the width of the band gap in the new model of the band structure, LiNaSO4. It is assumed that the appearance of intrinsic luminescence and the formation of capture centers are associated with low-energy transitions from the 1t1 orbitals of the valence band of the anionic complex to the s-state of the cation in the conduction band.