The role of three-body interactions in calculating the thermodynamic properties of argon crystal

On the basis of the un-symmetrized self-consistent field method(USCFM), some thermodynamic properties of crystalline argon Ar are calculated in this work with (and without) taking into consideration the influence of three-body interactions. These properties are: The potential energy, the isochoric and isobaric heat capacities, thermal and adiabatic bulk modulus. This was done in order to evaluate the influence of three-body interactions on the above mentioned properties. In addition to the above, our results are compared with the available experimental and theoretical ones. It is found that our results, except Cv and Cp, are in a good agreement with the experimental results as well as with results of other methods. Concerning Cv and Cp behavior, it is found that, the agreement with the experimental results is acceptable at moderate and elevated temperature while it is very poor at low temperatures because of neglecting quantum effects. (author)