Effect of Phonon Anharmonicity on the Thermophysical and Elastic Properties of Platinum

A self-consistent thermodynamic model describing the effect of lattice anharmonicity on the elastic and thermophysical properties of platinum has been developed. The temperature dependences of the mean- square displacement of lattice atoms from the equilibrium positions, the lattice components of the specific heat, the thermal expansion coefficient, the molar volume, and the bulk modulus have been calculated using the developed model. A strong enhancement of the effect of lattice anharmonicity on the thermophysical and elastic properties at temperatures much higher than the Debye temperature has been revealed. The Grüneisen param- eters of platinum and palladium have been estimated and compared.