We propose a model for energetics of solids, based on a direct solution for the density matrix directly from the Hamiltonian. The approach is suitable for obtaining an approximate, finite-ranged density matrix in a basis of localized orbitals. This scheme scales linearly with the size of the system, and should represent an improvement over the much-used embedded-atom, cluster-functional, and bond-order potentials.

• Received 10 August 1992

DOI:https://doi.org/10.1103/PhysRevB.47.10895