Toward the complete range separation of non-hybrid exchange-correlation functional.

Abstract

In this study, we use a very simple scheme to achieve range separation of a total exchange-correlation functional. We have utilized this methodology to combine a short-range pure density functional theory (DFT) functional with a corresponding long-range pure DFT, leading to a "Range-separated eXchange-Correlation" (RXC) scheme. By examining the performance of a range of standard exchange-correlation functionals for prototypical short- and long-range properties, we have chosen B-LYP as the short-range functional and PBE-B95 as the long-range counterpart. The results of our testing using a more diverse range of data sets show that, for properties that we deem to be short-range in nature, the performance of this prescribed RXC-DFT protocol does resemble that of B-LYP in most cases, and vice versa. Thus, this RXC-DFT protocol already provides meaningful numerical results. Furthermore, we envisage that the general RXC scheme can be easily implemented in computational chemistry software packages. This study paves a way for further refinement of such a range-separation technique for the development of better performing DFT procedures.