范德华作用的量子化学研究(四)

Quantum Chemical Study of the Role of the Van Der Waals Interaction (4)

本文通过耦合簇CCSD等量子化学方法,计算了一些分子间范德华作用体系:氢分子晶面(H2)6,氢分子晶胞((H2)6)2,苯分子二聚体(C6H6)2,以及氢分子与氟化氢二聚体HH----FH。并作了相应的电子密度差图形。通过图形分析,研究了范德华作用,讨论了取向力、诱导力,分析了配位键、氢键、范德华作用之间的异同。归纳了分子间范德华作用的机理、特征。范德华作用与共价键、氢键,有着统一的本质:在一定的格局下共享电子产生引力,来抗衡核与核、电子与电子的排斥,并达到平衡。

In this work, via coupled-cluster CCSD and other quantum chemistry methods, some systems with intermolecular van der Waals (vdW) interactions are calculated, including crystal face of molecular hydrogen(H2)6, crystal cell of molecular hydrogen((H2)6)2, benzene dimer(C6H6)2as well as dimer between molecular hydrogen and hydrogen fluoride HH----FH. Corresponding difference maps of electron density are also plotted. In terms of graphical analysis, vdW interaction is investigated;orientation force, induction force and dispersion force are discussed;the similarities and differences between coordinate bonds, hydrogen bonds and vdW interactions are analyzed. The mechanism and characteristic of intermolecular vdW interaction are concluded. vdW interaction has identical nature as covalent bonds and hydrogen bonds, namely under certain circumstances, shared electrons form attractive force to contend with the nuclear- nuclear and electron-electron repulsive force, and eventually achieve balance.