Thermal and elastic properties of solid sodium based on an effective interionic potential

Basing on the Schiff effective interionic potential which has oscillatory character we have calculated a complete set of equilibrium thermodynamic properties of solid sodium at normal pressure above the martensitic transition temperature. To take into account the anharmonicity which is strong at high temperatures we use the correlative method of unsymmetrized self-consistent field elaborated previously. Our results are in agreement with measured values and with available data of computer simulations. We discuss the thermodynamic stability of the b.c.c. lattice of sodium and the mechanism of its loss. The metastability of a hypothetical f.c.c. lattice with Schiff potential is discussed.