Empirical functionals for reduced-density-matrix-functional theory
Empirical functionals for reduced-density-matrix-functional theory
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降密度矩阵泛函理论的经验泛函
DOI：
10.1103/physreva.77.032509
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发表时间：
2008
影响因子：
2.9
通讯作者：
N. Lathiotakis
中科院分区：
文献类型：
--
作者：
M. A. L. Marques;M. A. L. Marques;N. Lathiotakis
我们提出了在降密度矩阵泛函理论（RDMFT）中使用的完全经验交换相关泛函。这些是流行的 $J\text{\ensuremath{-}}K$ 形式 [仅涉及自然轨道上的库仑- $(J)$ 和交换- $(K)$ 型积分]，其中乘以 Fock 轨道项的占据数函数被写为 Pad\'e 近似。 Pad\'e 近似系数针对八个分子的测试集进行优化，然后针对更大的 $35\phantom{\rule{0.3em}{0ex}}\text{molecules}$ 集进行细化。尝试了两种不同的方法，要么保留自交互项，要么从泛函中明确删除它们。由此获得的泛函涉及很少的参数，但能够优于其他 RDMFT 泛函，产生平均而言甚至略优于二阶 M\o{}ller-Plesset 理论的相关能。
We present fully empirical exchange-correlation functionals to be used within reduced-density-matrix-functional theory (RDMFT). These are of the popular $J\text{\ensuremath{-}}K$ form [involving only Coulomb- $(J)$ and exchange- $(K)$ type integrals over the natural orbitals], where the function of the occupation numbers that multiplies the Fock orbital term is written as a Pad\'e approximant. The coefficients of the Pad\'e approximant are optimized for a test set of eight molecules, and then refined for a larger set of $35\phantom{\rule{0.3em}{0ex}}\text{molecules}$. Two different approaches were tried, either keeping the self-interaction terms, or by removing them explicitly from the functional. The functionals thus obtained involve very few parameters, but are able to outperform other RDMFT functionals, yielding correlation energies that are, on average, even slightly better than second-order M\o{}ller-Plesset theory.