Laplacian相关的动能密度模型：在亚广义梯度近似泛函的子系统密度泛函理论中的应用
Laplacian-dependent models of the kinetic energy density: Applications in subsystem density functional theory with meta-generalized gradient approximation functionals
摘要：
动能密度（KED）半局域模型的发展是密度泛函理论（DFT）的一个重要课题。这对于子系统DFT尤其如此，其中这些模型对于构建所需的非添加剂嵌入贡献是必要的。特别是，这些模型也可以有效地取代确切的KED在元广义梯度近似（元GGA）交换相关泛函，允许扩展子系统DFT的适用性的元GGA理论水平。在这里，我们提出了一个二维扫描的半局部KED模型的线性泛函的减少梯度和减少拉普拉斯，原子和弱束缚的分子系统。我们发现，有几种模型可以表现良好，但在任何情况下，拉普拉斯的贡献是非常重要的模型的KED的本地功能。事实上，一个简单的模型构建的总和的Ekas-Fermi KED和1/6的拉普拉斯密度产生最好的精度为原子和弱束缚的分子系统。这些KED模型进行了测试内的子系统DFT与各种元GGA交换相关泛函的非键合系统，显示出良好的精度的方法。
英文摘要：
The development of semilocal models for the kinetic energy density (KED) is an important topic in density functional theory (DFT). This is especially true for subsystem DFT, where these models are necessary to construct the required non-additive embedding contributions. In particular, these models can also be efficiently employed to replace the exact KED in meta-Generalized Gradient Approximation (meta-GGA) exchange-correlation functionals allowing to extend the subsystem DFT applicability to the meta-GGA level of theory. Here, we present a two-dimensional scan of semilocal KED models as linear functionals of the reduced gradient and of the reduced Laplacian, for atoms and weakly-bound molecular systems. We find that several models can perform well but in any case the Laplacian contribution is extremely important to model the local features of the KED. Indeed a simple model constructed as the sum of Thomas-Fermi KED and 1/6 of the Laplacian of the density yields the best accuracy for atoms and weakly-bound molecular systems. These KED models are tested within subsystem DFT with various meta-GGA exchange-correlation functionals for non-bonded systems, showing a good accuracy of the method.
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