Shao Xuecheng, Mi Wenhui, Pavanello Michele
Department of Chemistry, Rutgers University, Newark, New Jersey 07102, United States.
Department of Physics, Rutgers University, Newark, New Jersey 07102, United States.
J Chem Theory Comput. 2021 Jun 8;17(6):3455-3461. doi: 10.1021/acs.jctc.1c00283. Epub 2021 May 13.
The key feature of nonlocal kinetic energy functionals is their ability to reduce to the Thomas-Fermi functional in the regions of high density and to the von Weizsäcker functional in the region of low-density/high reduced density gradient. This behavior is crucial when these functionals are employed in subsystem DFT simulations to approximate the nonadditive kinetic energy. We propose a GGA nonadditive kinetic energy functional which mimics the good behavior of nonlocal functionals, retaining the computational complexity of typical semilocal functionals. Crucially, this functional depends on the inter-subsystem density overlap. The new functional reproduces Kohn-Sham DFT and benchmark CCSD(T) interaction energies of weakly interacting dimers in the S22-5 and S66 test sets with a mean absolute deviation well below 1 kcal/mol.
非局部动能泛函的关键特性在于，在高密度区域它们能够简化为托马斯 - 费米泛函，而在低密度/高约化密度梯度区域则能简化为冯·魏茨泽克泛函。当这些泛函用于子系统密度泛函理论（DFT）模拟以近似非加和动能时，这种行为至关重要。我们提出了一种广义梯度近似（GGA）非加和动能泛函，它模仿了非局部泛函的良好行为，同时保留了典型半局部泛函的计算复杂度。至关重要的是，该泛函依赖于子系统间的密度重叠。新泛函在S22 - 5和S66测试集上再现了弱相互作用二聚体的科恩 - 沈DFT和基准耦合簇单双激发（CCSD(T)）相互作用能，平均绝对偏差远低于1千卡/摩尔。
