A simple statistical model of a condensed system with pair particle interaction, which was described by the Lennard-Jones potential, was proposed. Under the assumption that the probability of filling a micro-cell pair was equal to the product of the probabilities of filling single cells, a variational problem on minimization of free energy by the model’s internal parameter was formulated. An analytical expression for the addition to the vibrational specific heat of a molecular vacancy crystal was obtained. A refined model in which the correlation in filling microcell pairs with pores was allowed for was considered; a refined expression for the addition to the vibrational specific heat, which contained the corresponding small corrections, was obtained.

Molecular-Statistical Description of the Specific Heat of Thermal-Vacancy Crystals 1. Statistical Model of Allowance for the Contribution of the Vacancy Subsystem to the Lattice Specific Heat of Crystals. I.I.Narkevich, A.V.Zharkevich, E.V.Farafontova: Journal of Engineering Physics and Thermophysics, 2010, 83[2], 421-30