Semiempirical Estimation of Thermal Expansion Coefficients and Isobaric Heat Capacities of Fluorite-Type Compounds

The thermal expansion coefficients and isobaric heat capacities of fluorite-type compounds have been estimated using the Morse potential and the Debye model. The Born repulsion parameters of various compounds, which are necessary for determining the parameters of the Morse potential, have been determined empirically for elements belonging to every period of the periodic table. Using the parameters thus determined, the Debye temperature, the thermal expansion coefficient, and the Gruneisen constant of fluorite-type compounds have been calculated and then the isochoric and the isobaric heat capacities have been calculated over a wide range of temperatures. The calculated thermal expansion coefficients and isobaric heat capacities thus obtained are in good agreement with experimental values except for the anomalous temperature regions due to vacancy formation and phase transitions.