DENSITY-FUNCTIONAL WANNIER FUNCTION-THEORY FOR SYSTEMS OF VERY MANY ATOMS

Conventional theoretical methods for calculating ground-state energies of multi-atom systems in general become impractical when the number of atoms, N(a), exceeds approximately 10(2), because the computing time rises with N(a)alpha, where 2 < alpha < 3. Using so-called generalized Wannier functions in conjunction with density functional theory, we develop a procedure for the direct calculation of the GWFs (not requiring single particle eigenfunctions) whose computing time behaves as N(a) The method allows the transfer of GWFs from one physical or chemical system to another.