A divide-and-conquer implementation of the discrete variational DFT method for large molecular and solid systems

In this paper a novel density functional theory code is described that implements Yang's divide-and-conquer approach in the framework of the discrete variational method. The primary aim of the software is the rapid computation of approximate electron densities and density of states for a given arrangement of atoms. By using moderately sized grids and compact basis and density fit function sets, a high degree of efficiency is achieved. Through the use of the example of linear alkane chains, it is demonstrated that the performance of the method scales linearly with respect to system size for up to more than 1000 atoms. Details of the implementation are given where emphasis is placed on the approximations made and how linear scaling is achieved. Finally, calculations on some example structures will be presented to survey possible applications of the code. (C) 1998 Academic Press.