The Density functional triple jump

Abstract

We consider a general framework for jumping from a low-cost primary density functional calculation toward a higher quality secondary one, at a significantly reduced cost compared to the full secondary calculation. Three key parameters, the basis, functional and quadrature grid, can all be varied, either independently or in combination, and each combination can be viewed as a vertex on the DFT triple-jump cube. We will discuss several vertices on this cube with respect to cost savings and accuracy compared to the full secondary calculation and point out that the various dual-basis and dual-level3 are special cases of our approach. Results for a range of molecules and reactions show energies at the popular B3LYP/6-311+G(3df,2p)/(75,302) level can be accurately estimated from primary calculations at the relatively economical BLYP/6-31G(d)/SG-0 level