Thermal equation of state of tantalum
Abstract
We have investigated the thermal equation of state of bcc tantalum from first principles using the fullpotential linearized augmented plane wave (LAPW) and mixedbasis pseudopotential methods for pressures up to 300 GPa and temperatures up to 10 000 K. The equation of state at zero temperature was computed using LAPW. For finite temperatures, mixed basis pseudopotential computations were performed for 54 atom supercells. The vibrational contributions were obtained by computing the partition function using the particle in a cell model, and the finitetemperature electronicfree energy was obtained from the LAPW band structures. We discuss the behavior of thermal equation of state parameters such as the Grüneisen parameter γ, the thermal expansivity α, and the AndersonGrüneisen parameter δ_{T} as functions of pressure and temperature. The calculated Hugoniot shows excellent agreement with shockwave experiments. An electronic topological transition was found at approximately 200 GPa.
 Publication:

Physical Review B
 Pub Date:
 June 2001
 DOI:
 10.1103/PhysRevB.63.224101
 arXiv:
 arXiv:condmat/0006213
 Bibcode:
 2001PhRvB..63v4101C
 Keywords:

 64.30.+t;
 05.70.Ce;
 71.20.Be;
 65.20.+w;
 Equations of state of specific substances;
 Thermodynamic functions and equations of state;
 Transition metals and alloys;
 Thermal properties of liquids: heat capacity thermal expansion etc.;
 Condensed Matter  Materials Science
 EPrint:
 Phys. Rev. B 63, 224101 (2001).