# Ground-state thermomechanical properties of some cubic elements in the local-density formalism

## Abstract

We show that the cohesive energy, lattice constant, and bulk modulus of Li, Be, Na, Al, Ar, K, Ca, and Cu can be calculated using the local-density scheme of Kohn and Sham, to within 20%, 0.3 Bohr radii, and 10%, respectively, of experimental values. These calculations are truly a priori in that the only inputs are the atomic number Z and the zero-point lattice properties. Self-consistent crystal calculations were performed using the muffin-tin approximation, and atomic calculations were performed using the spin-polarized exchange-correlation functional constructed by von Barth and Hedin. The results show that these approximations are adequate for computing the equilibrium properties of crystals (errors in the computed pressure-volume relations are less than 10 kbar), but errors occur in the atomic calculations for atoms with more than one electron outside a closed shell, and possibly in the muffin-tin approximation for transition-element crystals. © 1975 The American Physical Society.