Abstract: Cohesion in d-state metals at high pressures​

U. Walzer. Cohesion in d-state metals at high pressures. Phys. Status Solidi (b), 140:377-391, 1987.

Cohesion in d-state metals at high pressures

U. Walzer

Abstract

A description of the d-band structure in which the pseudopotential theory is combined with the muffin-tin orbital theory serves for the calculation of the cohesive properties of d-state metals. The coupling of free-electron states and local, non-overlapping d-states is also taken into account. On this basis, two new models are developed. In both the models, it is assumed that the ratio of nearest-neighbour separation to the atomic radius is independent of the pressure. In the first model (MB), the additional condition is that a redistribution of electrons between the two outer shells, which are not completely filled, is permissible. In the second model (MC), the requirement is that for elements with a filled d-shell the theoretical bulk modulus at vanishing pressure is exactly equal to the experimental bulk modulus at vanishing pressure and that the pressure exactly vanishes for the zero-pressure volume. In a comparison with various kinds of measured values, MC proves to be particular successful for all d-state metals except Sc, Ti, and Nb. In both the models, the initial pressure derivative of the bulk modulus is not an input parameter, but can be predicted.

Key words: d-state metals, transition metals, solid-state physics, metals, pseudopotential, muffin-tin orbital theory, cohesion, outer shell, density functional formalism, atomic sphere approximation, d-electrons, Schrödinger equation, Madelung energy, electron gas, static pressure, Hugoniot pressure, high pressure, equation of state

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