Elastic and thermal properties of osmium under pressure.

In this study, first-principles calculations of the crystal structure and the elastic properties of osmium have been carried out using the plane-wave pseudopotential density functional theory method. The calculated values are in very good agreement with experimental data as well as with some of the existing model calculations. The pressure dependence of the elastic constants, the aggregate elastic moduli (B, G, E), the Poisson's ratio, the Lame constant, the compressibility, the longitudinal wave and transverse wave velocities, the Debye temperature and the elastic anisotropy have been investigated. Moreover, the temperature and pressure dependence of the thermal expansion coefficient is estimated from the Debye approximation. [ABSTRACT FROM AUTHOR]