Thermal Shifts and Electron-Phonon Coupling Parameters for the Three Luminescence Lines of 5 D J→7 F J in SrFCl:Sm2+ Crystal

Abstract

Abstract The thermal blue shifts of three spectral lines E 1(5 D 0→7 F 0), E 2(5 D 0→7 F 1), and E 3(5 D 1→7 F 0) in SrFCl:Sm2+ crystal are investigated by a complete expression consisting of both the static contribution due to lattice thermal expansion and the vibrational contribution owing to electron-phonon interaction. The obtained true electron-phonon coupling parameters α′ in both sign and magnitude are considerably different from the apparent electron-phonon coupling parameters α acquired in the previous paper by considering only the vibrational contribution. It is suggested that differing from the simple expression including only the vibrational contribution (many authors thought that it cannot be used to explain the thermal blue shifts), the complete expression containing both the vibrational and static contributions is effective in the studies of thermal shift (whether red shift or blue shift) and true electron-phonon coupling parameter for a spectral line in crystals.