Department of Chemistry, Duke University, Durham, NC 27708.
Department of Chemistry, Duke University, Durham, NC 27708;
Proc Natl Acad Sci U S A. 2018 Sep 25;115(39):9678-9683. doi: 10.1073/pnas.1807095115. Epub 2018 Sep 10.
An effective fractional-spin correction is developed to describe static/strong correlation in density functional theory. Combined with the fractional-charge correction from recently developed localized orbital scaling correction (LOSC), a functional, the fractional-spin LOSC (FSLOSC), is proposed. FSLOSC, a correction to commonly used functional approximations, introduces the explicit derivative discontinuity and largely restores the flat-plane behavior of electronic energy at fractional charges and fractional spins. In addition to improving results from conventional functionals for the prediction of ionization potentials, electron affinities, quasiparticle spectra, and reaction barrier heights, FSLOSC properly describes the dissociation of ionic species, single bonds, and multiple bonds without breaking space or spin symmetry and corrects the spurious fractional-charge dissociation of heteroatom molecules of conventional functionals. Thus, FSLOSC demonstrates success in reducing delocalization error and including strong correlation, within low-cost density functional approximation.
发展了一种有效的分数自旋修正方法，以描述密度泛函理论中的静态/强关联。结合最近开发的局域轨道标度修正（LOSC）的分数电荷修正，提出了一个泛函，即分数自旋 LOSC（FSLOSC）。FSLOSC 是对常用功能近似的修正，引入了显式导数不连续性，并在分数电荷和分数自旋时大大恢复了电子能量的平面行为。除了改善传统泛函在预测电离能、电子亲和能、准粒子谱和反应势垒高度方面的结果外，FSLOSC 还正确描述了离子物种、单键和多键的解离，而不会破坏空间或自旋对称性，并纠正了传统泛函中杂原子分子的虚假分数电荷解离。因此，FSLOSC 在低成本密度泛函近似中成功地减少了离域误差并包含了强关联。
