The P-V-T equation of state (EoS) models of Birch-Murnaghan, Vinet and Poirier-Tarantola have been compared with one another and discussed in the light of their ability to reproduce thermoelastic functions and parameters by means of fitting to pressure-volume-temperature data artificially generated for spinel, corundum and forsterite. Numerical simulations relying upon semi-empirical potentials, lattice dynamics and the quasiharmonic approximation have been used to generate P-V-T data. The results obtained indicate that all the P-V-T- EoSs tested predict bulk modulus at ambient conditions with errors confined, at worst, within a few percent, and reproduce correctly its dependence on temperature. The derivatives of the bulk modulus versus P and PT are less satisfactorily modelled. The bulk thermal expansion is determined by EoSs within a few percent error, but the deviations increase significantly if the approximation of linear dependence of EoS on temperature is used (linearised thermal pressure model).
Pressure volume temperature equations of state: a comparative study based on numerical simulations / A. Pavese. - In: PHYSICS AND CHEMISTRY OF MINERALS. - ISSN 0342-1791. - 29:1(2002), pp. 43-51.
Pressure volume temperature equations of state: a comparative study based on numerical simulations
A. PavesePrimo
2002
Abstract
The P-V-T equation of state (EoS) models of Birch-Murnaghan, Vinet and Poirier-Tarantola have been compared with one another and discussed in the light of their ability to reproduce thermoelastic functions and parameters by means of fitting to pressure-volume-temperature data artificially generated for spinel, corundum and forsterite. Numerical simulations relying upon semi-empirical potentials, lattice dynamics and the quasiharmonic approximation have been used to generate P-V-T data. The results obtained indicate that all the P-V-T- EoSs tested predict bulk modulus at ambient conditions with errors confined, at worst, within a few percent, and reproduce correctly its dependence on temperature. The derivatives of the bulk modulus versus P and PT are less satisfactorily modelled. The bulk thermal expansion is determined by EoSs within a few percent error, but the deviations increase significantly if the approximation of linear dependence of EoS on temperature is used (linearised thermal pressure model).Pubblicazioni consigliate
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