期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2018
卷号：115
期号：10
页码：2287-2292
DOI：10.1073/pnas.1713047115
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Recently, it was argued [Medvedev MG, et al. (2017) Science 355:49–52] that the development of density functional approximations (DFAs) is “straying from the path toward the exact functional.” The exact functional should yield both exact energy and density for a system of interest; nevertheless, they found that many heavily fitted functionals for molecular energies actually lead to poor electron densities of atoms. They also observed a trend that, for the nonempirical and few-parameter functionals, densities can be improved as one climbs up the first four rungs of the Jacob’s ladder of DFAs. The XYG3 type of doubly hybrid functionals (xDHs) represents a less-empirical and fewer-parameter functional on the top fifth rung, in which both the Hartree–Fock-like exchange and the second-order perturbative (MP2-like) correlation are hybridized with the low rung functionals. Here, we show that xDHs can well describe both density and energy for the same atomic set of Medvedev et al., showing that the latter trend can well be extended to the top fifth rung.
关键词：density functional theory ; electron density ; electronic structure ; doubly hybrid functional ; XYG3
Loading...
