PNNL

Abstract

The central premise of density functional methods is that functionals of the electron density describe the properties of many-electron systems, including quantum effects such as electron exchange and correlation. In practice, such methods have demonstrated accuracies comparable to those of more computationally intensive quantum methods; however, they are limited by their demand of computational power. In this report we describe an alternative approach to constructing the initial electron density that serves as the starting point for density functional methods. In our method, the total density is constructed piecewise from fragments. Assuming that fragment densities can be computed efficiently, this leads to significant improvements in the overall calculation effort. We report results of calculations in several model systems.