Infrared Reflectivity and Raman Scattering of Mg₂SiO₄ Single Crystal

Abstract

Abstract The lattice vibrations of Mg 2 SiO 4 forsterite single crystal have been studied using infrared and Raman techniques. The site symmetry method allows to study the degeneracy lifting of the silicate ion vibrational levels and to assign the modes of vibration (45 infrared active modes and 36 Raman active modes), as internal or external. The analysis of the reflectivity data between 150 and 10000 cm −l by classical dispersion theory allows to find the oscillator parameter values. Most of the infrared lattice bands could be identified. All the predicted modes have been observed in the Raman spectra and the vl 1 v 2 , and v 4 lines have been identified. For some modes, specially in the low frequency range, the difference between internal and external modes is not obvious, taking into account the SiO 4 tetrahedra deformation.