Van der Waals crystals
Reverting to an investigation of thermal vacancies in simple Van der Waals crystals [phys. stat. sol. (b) 101, 95 (1980)] we take into account a possibility of forming their bonded complexes, in particular divacancies.
We use the correlative method of unsymmetrized self-consistent field (CUSF) that enables one to include the strong anharmonicity of the lattice vibrations.
We have calculated the parameters of the vacancy formation, the vacancy and divacancy concentration in solid Ar and contribution of the defects to its equilibrium thermodynamic properties, depending on the temperature and pressure, such contributions to components of elastic tensor being first studied. . We also investigate the influence of defects on the thermodynamic stability of crystal lattices