SELFCONSISTENT MODEL FOR THE CALCULATION OF THERMOELASTIC AND CALORICPROPERTIES OF MINERALS

A selfconsistent model for the caculation of thermoelastic and caloric properties of minerals within the broad P - T range is presented. The model is based on the specific type of oscillation spectrum suggested by Kiffer and on Born-Mayer potential. Main peculiarity of this model includes the consistency of the oscillatory spectrum with the potenti al ascribing the dependence of static lattice energy in relation to it s volume. The consistency is achieved by the selection of Born-Mayer p otential parameters so as to satisfy the equation of state along the z ero isobar. The second peculiarity of the model involves the possibili ty to use the equilibrium isotopic factors (beta-factors) as in put da ta saong with traditional ones such as specific heat capacity, heat ex tension, elastic compression module and its isothermal derivative with respect to pressure. Such approach makes possible to derive more reli able oscilation spectrum parameters in high frequency interval the lat ter being especially important for minerals with large number of atoms in the elementary cell. Our model was checked on such examples as per iclase, calcium oxide, corundum, forsterite and grossular and indicate d fair possibilities for its application for the calculation or thermo dynamic properties of minerals and its extrapolation in such P - T int erval where such data are scarce of absent. It seems necessary to appl y the model for calculation of reference equation of state for mineral s having no phase transformations in wide P-T range for the purpose of calibrated standards. Corresponding software for IBM is developed.