Computer Design of Materials: PUBLICATIONS

Pressure induced transitions in calcium; a tight-binding approach

Guan Ming Wang*, D. A. Papaconstantopoulos*+, and Estela Blaisten-Barojas*

(*)School of Computational Sciences, George Mason University, Fairfax, VA 22030
(+)Center for Computational Materials Science, Naval Research Laboratory, Washington DC 20375

A tight-binding hamiltonian for calcium is built with a high precision parametrization technique based on density functional calculations of the energy bands and the total energy at various lattice volumes. The new set of tight-binding parameters is appropriate to study phenomena under pressures as high as 20 GPa. Specifically, both the metal to nonmetal transition at 4 GPa and the structural transition fcc to bcc at 19 GPa are well reproduced. These transitions and several static properties are in excellent agreement with experiments. Phonon frequencies, plasmon energy, melting temperature and the coefficient of thermal expansion were calculated with a molecular dynamics scheme of this tight-binding hamiltonian.

J. of Phys. and Chem of Solids, accepted Feb. 2002.
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