DENSITY-FUNCTIONAL THEORY FOR SYSTEMS OF VERY MANY ATOMS

The standard Kohn-Sham formulation of density functional theory (DFT) is limited, for practical reasons, to systems of less than about 50-100 atoms. The computational effort scales as N-at(alpha), where N-at is the number of atoms and 2 < alpha < 3. (By comparison, conventional configuration interaction methods are limited to 5-10 atom systems.) This article deals with the prospect of practical methods that scale linearly in N-at and may thus allow calculations for systems of 10(3)-10(4) atoms. The physical reason (''near-sightedness'') for linear scaling is presented. Implementations of linear scaling DFT by the use of generalized Wannier functions or the one-particle density matrix are discussed. (C) 1995 John Wiley & Sons, Inc.