IN SITU TEMPERATURE-DEPENDENT RAMAN SPECTROSCOPY AND LATTICE DYNAMICS OF SCHEELITE AND SCHEELITE-LIKE COMPOUNDS

Here we present the results from an in situ Raman thermal spectroscopy study on specific features of the lattice dynamics of scheelite-type compounds (natural and synthetic scheelite, synthetic CaMoO4 and SrMoO4) in the temperature range of 83–873 K. Spectroscopic data processing has been carried out based on both classical "peak fitting" and statistical approaches. It has been suggested that an increase in temperature causes nonuniformity of MoO4 and WO4 tetrahedra transformation. It has been assumed that dynamics in thermal expansion of unit cells of Ca-containing compounds is slower than that in thermal expansion of WO4 (MoO4) polyhedral. This diffence is mainly due to the fact that thermal expansion is mainly defined by the expansion of CaO8 (SrO8) polyhedra.