2 S ep 1 99 7 Thermodynamic and electronic properties of a tight - binding lattice - gas model

Thermodynamic and electronic properties are obtained for a lattice-gas model fluid with self-consistent, partial, occupation of its sites; the self consistency consists in obtaining ionic configurations from grand-canonical Monte Carlo simulations based on fits to the exact, electronic, tight-binding energies of isothermal ensembles of those same ionic configurations. The energy of an ion is found to be a concave-up function of its local coordination. Liquidvapor coexistence densities and the electrical conductivity, which shows a metal-nonmetal transition, have been obtained.