| Abstract
| - We study the influence of thermal vacancies on equilibrium thermodynamic properties of the high-temperaturephase of fullerites taking into account the strong anharmonicity of the lattice vibrations. Treating a crystalwith point defects as a quasi-multicomponent system and using the correlative method of the unsymmetrizedself-consistent field and the Girifalco interaction potential for the molecular subsystem, we have obtained thevacancy formation parameters for the C60 fullerite. We also take into account the divacancies. The influenceof the lattice defects on the specific heats of fullerites is negligible, since a dominant contribution to them isgiven by intramolecular degrees of freedom. We have calculated the contributions of vacancies to variousthermodynamic properties, the volume thermal expansion coefficient, the isothermal bulk modulus, and thecomponents of the isothermal elastic tensor, depending on the temperature and pressure. Near the estimatedtriple point, these contributions run to more than 10% and increase still further at a metastable region. Wealso discuss the influence of defects on the thermodynamic stability of fullerites.
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