范德华作用的量子化学研究(一)

Quantum Chemical Study of the Role of the van der Waals Interaction (1)

摘要: 用量子化学耦合簇CCSD/aug-cc-pVTz等方法，计算了稀有气体分子，作了电子密度差及图形，通过图形解读了范德华作用的本质和形成机理。提出了范德华作用的量子化学图景是：原子或分子配对的电子云球相碰，由于Pauli互斥，电子云球变形，形成了电子一定程度的回避，同时产生了一定程度的电子共享，达到吸引和排斥的平衡，从而构成了范德华力。认为范德华作用的本质也是一种波函数在起作用，并因此构成了核之间吸引共享电子，也是一种化学作用力。 In this paper, coupled-cluster CCSD/aug-cc-pVTz and related quantum chemistry methods are employed to calculate rare gas molecules and plot figures of electron density differences, the nature and formation mechanism of van der Waals interaction are interpreted graphically. We propose a quantum chemistry picture for van der Waals interac- tion: In the process of the collision of paired electron cloud of atoms or molecules, electron cloud balls deform due to Pauli repulsion effect, and a certain degree of electron avoidance as well as electron sharing are formed. The van der Waals force is the consequence of the equilibrium between the attraction and repulsion. We believe that the nature of van der Waals effect is acting of wavefunction, which results in the internuclear shared electron, so van der Waals ef- fect can also be seen as a kind of chemical force.