THERMAL EXPANSION AND VIBRATIONAL SPECTRA OF PARATELLURITE IN QUASI-HARMONIC APPROXIMATION

Thermal expansion of the paratellurite is modeled with density functional theory calculations using quasi-harmonic approximation.The calculations qualitatively reproduce anisotropy of the thermal expansion and demonstrate good correspondence to the experimental values at low temperatures.Lattice vibrations at the -point are described in terms of the motion of the TeO2 fragments, and the temperature shift of frequencies in vibrational spectra is evaluated.