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在烷烃及其衍生物中,通常认为没有π键,更没有共轭π键,为什么从光电子能谱得出的分子轨道能级也符合同系能级线性规律,即: E(N,k)=a+bX(N,k),(1) X(N,k)=((2k-1)/k)sin((kπ)/(2N+1)) (2)呢?本文尝试对这一问题作一理论探讨。我们分析了用从头计算法求得的烷烃同系物的分子轨道系数矩阵,确认同样存在着共轭π型的分子轨道.例如,H-(CH_2)_n-H分子可以看作是由n个CH_2基团和两端各一个H原子所组成。每一个CH_2基团中C的平行的p轨道与两个H的s轨道之间有两种组合形式(如表1所示)。
In alkanes and their derivatives, it is generally considered that there is no π bond and no conjugated π bond. Therefore, the molecular orbital energy level derived from photoelectron spectroscopy also meets the linear law of homomorphism, that is: E (N, k) = (1) X (N, k) = ((2k -1) / k) sin ((kπ) / (2N + 1)) (2) A theoretical discussion of the problem. We have analyzed the molecular orbital matrix of alkane homologues calculated by ab initio method and confirmed the existence of conjugated π-type molecular orbitals. For example, the H- (CH 2) _n-H molecule can be viewed as a series of n CH 2 Group and one H atom at each end. There are two combinations of the parallel p orbitals of C in each CH 2 group and the orbitals of two Hs (as shown in Table 1).