Abstract: A new high-pressure equation of state for metals​

U. Walzer. A new high pressure equation of state for metals. High Temp. - High Pressures, 16:335-346, 1984.

A new high-pressure equation of state for metals

U. Walzer

Abstract

A new theory is developed for metals which permits calculation of the free energy, pressure, and bulk modulus and its pressure derivatives as a function of the relative volume. With free energy, not only attractive and repulsive lattice energy, but also the Fermi energy, exchange, and correlation energies of the electrons are accounted for. The theory exhibits a certain analogy to the statistical theories. The overestimation of electron density near the nucleus has been overcome by a quantum-mechanical theory by Goodisman, the result of which is used in the present theory. The computational expenditure, however, is reasonable also for the purpose of practical high-pressure research. Five well-known quantities serve as input parameters: atomic charge, valency, atomic volume, bulk modulus and its first derivative with respect to pressure for vanishing pressure. The curves calculated from the new `MY' equation of state are compared with high compression data of twenty metals. For seventeen metals good or very good agreement is obtained, for three, a reasonable agreement is obtained.

Key words: solid-state physics, equation of state, high pressure, metals, free energy, pressure, bulk modulus, relative volume, attractive lattice energy, repulsive lattice energy, Fermi energy, exchange energy, correlation energy, electrons, statistical theory, electron density, nucleus, atomic charge, Lennard-Jones potential, Thomas-Fermi, Hartree-Fock, Mie-Grüneisen equation

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