摘要
Hund规则的传统解释是利用一级微扰理论并假定单重态减三重态的能量差等于其电子排斥能的差,即体系能量降低完全是由于电子排斥能减小的结果。这是一个误解。实际上由于轨道收缩,具有较低能量的状态有较大的电子排斥能,但也有远大于电子排斥能的电核吸引能。在多重态中,决定能量变化是电核吸引能而不是电子排斥能。
The traditional explanation for Hund's rules uses first order perturbation theory and assumes that a singlet minus triplet energy difference △E equals the difference in electron repulsion energy △(Vce), namely, The lowering of the total energy is ontirely due to the lowering of the electron repulsion energy. This is a misinterpretation. Actually, due to the contraction of the orbital, the state with lower energy in a multiplet has the larger electron repulsion energy but also by far the most negative electron-nuclear attraction enery. It is the electron nuclear attraction that dominates the energy behaviour in a multiplet and not the electron repulsion.
关键词
Hund规则
轨道收缩
自旋多重性
Huad's rule, Contraction of the orbital, Spin multiplicity
