Center for Biomolecular Nanotechnologies @UNILE, Istituto Italiano di Tecnologia (IIT), Via Barsanti, 73010 Arnesano (LE), Italy.
J Chem Phys. 2012 Jul 7;137(1):014102. doi: 10.1063/1.4730748.
We analyze the accuracy of the frozen density embedding (FDE) method, with hybrid and orbital-dependent exchange-correlation functionals, for the calculation of the total interaction energies of weakly interacting systems. Our investigation is motivated by the fact that these approaches require, in addition to the non-additive kinetic energy approximation, also approximate non-additive exact-exchange energies. Despite this further approximation, we find that the hybrid/orbital-dependent FDE approaches can reproduce the total energies with the same accuracy (about 1 mHa) as the one of conventional semi-local functionals. In many cases, thanks to error cancellation effects, hybrid/orbital-dependent approaches yield even the smallest error. A detailed energy-decomposition investigation is presented. Finally, the Becke-exchange functional is found to reproduce accurately the non-additive exact-exchange energies also for non-equilibrium geometries. These performances are rationalized in terms of a reduced-gradient decomposition of the non-additive exchange energy.
我们分析了冻结密度嵌入（FDE）方法的准确性，该方法结合了混合和轨道相关的交换相关泛函，用于计算弱相互作用体系的总相互作用能。我们的研究动机是，这些方法除了需要非加性动能近似外，还需要近似的非加性完全交换能。尽管有这种进一步的近似，我们发现混合/轨道相关的 FDE 方法可以以相同的精度（约 1 mHa）再现总能量，与传统的半局部泛函相同。在许多情况下，由于误差抵消效应，混合/轨道相关的方法甚至产生最小的误差。我们提出了详细的能量分解研究。最后，发现 Becke 交换泛函也可以准确地再现非平衡几何形状的非加性完全交换能。这些性能可以根据非加性交换能的梯度分解来合理化。
