Study of Vacancies Concentration in Crystal Argon as a Function of Temperature

In this work, the Unsymmetrized Self-Consistent Field Method (USCFM) which is applied in statistical physics for investigating physical properties of ideal solid state, is developed in order to take into consideration the crystalline defects of vacancy type. The mentioned development is based on quasi-chemical approximation in addition to the main principles of the above mentioned USCFM method. In order to investigate the affectivity of this development, the developed method is applied here to for calculating the vacancy concentration in crystalline argon as a function of temperature. The pair wise interaction forces are described by (6-12) Lennard-Jones potential while the three body interaction forces are described using Axillorod-Teller-Moto potential. The obtained results are compared with the available experimental and theoretical ones. It is found that the obtained, in this work, results, are in a good agreement with the experimental results as well as with results of other methods. (author)