Low-frequency Raman scattering from the 0.8ZnCl2–0.2AlCl3 glass-forming system

Abstract Low-frequency (5–120 cm−1) Raman scattering has been utilized to elucidate the temperature and polarization dependence of the quasi-elastic line and the Boson peak of the glass-forming salt 0.8ZnCl2–0.2AlCl3. A combined analysis, including both polarized and depolarized spectra, is being presented aimed at elucidating the frequency dependence of the scattered intensity at these low frequencies. The depolarization ratio of the pure Boson peak, after being disentangled form other contributions, namely the quasi-elastic line and low-lying vibrational modes, has been determined. The results reveal that the individual depolarization ratio of the Boson peak is strongly frequency dependent and different from the depolarization ratio of the quasi-elastic line. The temperature dependence of the quasi-elastic scattering intensity and of the maximum of the Boson peak has also been determined. The results are discussed in the framework of the current phenomenological status of the field.