Comparative Study of Potassium Halides Parameters with Many Body and van der Waals Three Body Force Shell Model [VTBFSM]

In present paper authors have used the theoretical model for calculation of value of different model parameters of potassium halides by using the effect of Many body (Puri and Verma, 1977) (Basic model for calculation and aurthor directley used the all calculated value of many body) and compared by van der Waals three body force shell model. In presence of both the effects, better result came, which gave good agreement between theoratical and experimental result. Inclusion of van der Waals interactions (VWI) and three body interactions in the framework of a polarizable rigid shell model (RSM) gave FOEC (Forth order elastic constants), which is not possible to calculate only by many body effects. By using VTBFS model we can calculate all parameters like second and third order elastic constants (SOEC, TOEC and FOEC), pressure derivatives of first, second order and cauchy relation. So calculated result, compared well with the corresponding experimental results, which provided important theoratical formula to calculate all the property of alkali halides, earth alkaline metal and also for chalcoganides. So inclusion of [VTBFSM] interactions gave complete theoratical investigation for all type crystals.