Temperature dependence of spectral positions and widths of 5D J → 7F J fluorescence lines originating from Sm2+ ions in SrFCl crystals

Abstract: The temperature dependence of the spectral positions and widths of the photoluminescence lines corresponding to the 5D0 → 7F0, 5D0 → 7F1 and 5D1 → 7F0 electronic transitions in Sm2+-doped SrFCl crystal was measured between 87 and 625K at ambient pressure. The temperature dependence of the homogeneous line width Γh (T) for all these transitions in the whole temperature range used can be described by the two-phonon Raman scattering of acoustic phonons with the Debye temperature TD ≈230K. Comparison of the temperature- and pressure-induced shifts revealed why all the emission lines studied show the blue temperature shifts. It is so because a greater part of the line shift is caused by the thermal expansion of the host crystal and not by enhancement of the electron–phonon coupling with increasing temperature. [ABSTRACT FROM AUTHOR]