Thermoelastic and structural properties of forsterite as a function of P and T: a computer simulation study, by semi-classical potentials

A theoretical study of some thermoelastic and structural properties of forsterite, at non-ambient conditions, is presented in this work. A site-dependent potential (NP) has been developed, and successfully used to carry out theoretical investigations on the lattice parameters, specific heat and tensorial elastic properties of forsterite, at P and T conditions representative of the actual thermobaric environment of the upper mantle of the Earth. Calculations have been performed in the framework of lattice dynamics and of quasi-harmonic approximation. The results, from high temperature or high pressure simulations, have been compared with experimental data. Calculations at high pressure and high temperature have provided unprecedented data, which are not easy to achieve experimentally. Received: October 10 1997 / Revised, accepted: January 26 1998