Gerber I C, Angyán J G
Laboratoire de Cristallographie et de Modélisation des Matériaux Minéraux et Biologiques, UMR 7036, CNRS, Nancy Université, B.P. 239, F-54506 Vandoeuvre-lès-Nancy, France.
J Chem Phys. 2007 Jan 28;126(4):044103. doi: 10.1063/1.2431644.
A satisfactory account of the van der Waals (vdW) (London dispersion) forces is, in general not possible by the Kohn-Sham method using standard local, semilocal generalized gradient approximation (GGA), or meta-GGA density functionals. The recently proposed range-separated hybrid (RSH) approach, supplemented by second order perturbational corrections (MP2) to include long-range dynamic correlation effects, offers a physically consistent, seamless description of dispersion forces. It is based on a rigorous generalization of the Kohn-Sham method, where long-range exchange and correlation effects are treated by wave function methods, while short-range electron exchange and correlation are handled by local or semilocal functionals. The method is tested on a series of rare gas dimers in comparison with standard wave function theory and density functional theory approaches. In contrast to the most successful exchange correlation functionals, which describe at best the vdW minimum, the RSH+MP2 approach is valid also in the asymptotic region and the potential curve displays the correct 1/R(6) behavior at large internuclear separations. In contrast to usual MP2 calculations, the basis set superposition error is considerably reduced, making RSH+MP2 an ideal tool for exploring the potential energy surface of weakly bound molecular complexes.
一般来说，使用标准的局域、半局域广义梯度近似（GGA）或元GGA密度泛函的Kohn-Sham方法，无法令人满意地描述范德华（vdW）（伦敦色散）力。最近提出的范围分离杂化（RSH）方法，辅以二阶微扰校正（MP2）以包含长程动态相关效应，提供了一种物理上一致、无缝的色散力描述。它基于Kohn-Sham方法的严格推广，其中长程交换和相关效应通过波函数方法处理，而短程电子交换和相关则由局域或半局域泛函处理。该方法与标准波函数理论和密度泛函理论方法相比，在一系列稀有气体二聚体上进行了测试。与最成功的交换相关泛函不同，后者充其量只能描述vdW最小值，而RSH+MP2方法在渐近区域也有效，并且势能曲线在大核间距时显示出正确的1/R(6)行为。与通常的MP2计算不同，基组叠加误差大大降低，使得RSH+MP2成为探索弱束缚分子复合物势能面的理想工具。
