Using molecular dynamic simulation data of calcite in a wide pressure range to calculate some of its thermodynamic properties via some universal equations of state

Abstract

Molecular dynamics, MD, simulation of calcite (CaCO3) is selected to compare the p-v-T behaviour of some universal equations of state, UEOS, for the temperature range 100 K ≤ T ≤ 800 K, and pressures up to 3000 kbar. The isothermal sets of p-v-T data generated by simulation were each fitted onto some three- and two-parameter EOSs including Parsafar and Mason (PM), Linear Isotherm Regularity (LIR), Birch-Murnaghan (BM), Shanker, Vinet, Baonza and Modified generalized Lennard–Jones (MGLJ) EOSs. It is found that the MD data satisfactorily fit these UEOS with reasonable precision. Some features for a good UEOS criteria such as temperature dependencies of coefficients, pressure deviation, isothermal bulk modulus and its derivative at the zero pressure limit, isobaric thermal expansion, pressure spinodal values and divergence of pseudo critical exponent either near to or far from the spinodal condition, and some regularities for calcite are investigated.