LINEAR SCALING FOR DENSITY FUNCTIONAL CALCULATIONS ON LARGE MOLECULES WITH THE DEFT SOFTWARE PACKAGE

Abstract

The new methods implemented within the DeFT density functional software package are outlined. Where appropriate, they are benchmarked against the conventional methods, which are prohibitively expensive for large systems due to their poor scaling with system size. Benchmark calculations on extended glycine polypeptides clearly demonstrate that linear scaling has been achieved for these first principles electronic structure calculations. Within the DeFT software package, a divide-and-conquer approach is instrumental in attaining this goal. The errors introduced by our divide-and-conquer approach are quantified and shown to be insignificant when compared to the inherent error in even the most accurate density functionals presently available. Calculations on molecules within the G2 dataset highlight the overall accuracy of the exchange-correlation functionals, orbital basis sets, auxiliary density fitting basis sets, and grids used within DeFT.