Vibrational spectra of Ca ₃SiO ₅: Ultraviolet laser Raman spectroscopy at high temperatures

The Raman spectra of Ca ₃SiO ₅ have been successfully obtained at temperatures up to 1353 K by a continuous-wave ultraviolet Raman spectroscopic system. The Raman spectra do not change significantly with an increase in temperature, despite triclinic (T) → monoclinic (M) → rhombohedral (R) transitions. The present result is described in terms of the parameter related to temperature variation at constant pressure, defined in a manner similar to the Gruneisen parameter. Raman bands located above 350 cm ^-1 show smaller values of the parameter than lower frequency modes, suggesting that these higher frequency modes are assigned to SiO ₄ internal modes.