Finite-temperature thermophysical properties of fcc-Ca
Department of Physics, Gujarat University, Ahmedabad, 380 009, Gujarat, India
2 Department of Physics, Sardar Patel University, Vallabh Vidyanagar, 388 120, Gujarat, India
Published online: 13 July 2007
At an extreme environment, such as high-temperature and high-pressure, harmonic theory has obvious limitations, where the anharmonic effects are influential in determining bulk properties of the materials. In this regard, necessity for incorporating anharmonicity through vibrational contribution and thermally excited electrons to the total free energy at finite temperatures is illustrated taking an example of divalent fcc-Ca. In this regard, we have employed a coupling scheme of combining recently proposed mean-field potential (MFP) with the local pseudopotential to obtain vibrational contribution to the total free energy. To access the applicability of the present coupling scheme, we have calculated temperature variation of several thermodynamical properties. Static EOS, shock Hugoniot and temperature along principal Hugoniot are also estimated. Results are satisfactorily compared with the other theoretical and experimental data and the use of local pseudopotential in conjunction with the MFP approach is justified.
PACS: 65.40.Ba – Heat capacity / 65.40.De – Thermal expansion; thermomechanical effects / 64.30.+t – Equations of state of specific substances
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2007