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用LEMAO-3G作为基函数集合,优选出苯分子的最佳调节因子组:ζ_(H1s)=1.26,ζ_(c1s)=1.0039,ζ_(c2σ)=1.1043,ζ(c2π)=1.00761.用此调节因子组计算得苯分子的总能量为-229.167274Hartrees,维里系数为1.00000.可较满意地符合量子力学基本原理的要求.所得各价轨道的能量与光电子能谱的实验数据基本相符,与Fischer Hjalmars和P.Siegbahn的很接近于Hartree-Fock极限的计算结果也颇为一致.但我们所用的基函数集合与他们所用的完全不同,而且简单得多.计算所得原子化能所占实验值的比例比由单纯“离域”观点计算的改进约17.6%.分析这些计算结果可得结论:苯分子的“芳香稳定性”的原因,不仅在于其环形共轭体系中诸轨道的“离域”效应,与之相对立而又与之紧密联系着的诸轨道的“收缩”或“定域”效应也起有十分重大的作用.并且σ-轨道的“离域”与“定域”在其中起有比π-轨道更为重要的作用当σ-轨道因“动能压力”的减小而发生程度很大的“收缩”(调节因子由1增大为1.1043)时,π轨道仅发生程度很小的“收缩”(调节因子由1仅增大为1.00761)而表现与σ-轨道相比较为弥散的状态.这一方面使得π-电子保留有较大的总能量,成为除π-轨道的“离域”效应外使π-电子具有较大的流动性因而能够很好地传递电子效应的另一个重要原因;另一方面,这却使得σ-电子的总能量降低得更多,因而使苯分子整体表现有较大的稳定性.我们认为这就是苯分子从总体看来较为稳定,但其π-电子却有较大的流动性的主要原因之所在.
Using LEMAO-3G as the basis set, the optimal regulators of benzene were optimized: ζ H1s = 1.26 ζ c1s = 1.0039 ζ c2σ = 1.1043 ζ c2π = 1.00761. The total energy of the benzene molecule calculated by the adjustment factor group is -229.167274 Hartrees, the Weirie coefficient is 1.00000, which can meet the requirements of the basic principles of quantum mechanics satisfactorily. The energy of each obtained orbital corresponds basically with the experimental data of photoelectron spectroscopy, and The Fischer Hjalmars and P.Siegbahn calculations are quite close to the Hartree-Fock limit, but the set of basis functions we used are quite different from the ones they used, and much simpler. Calculate the experimental values for the resulting atomic energies Is about 17.6% higher than that calculated from the viewpoint of pure “delocalization.” Analyzing these results leads to the conclusion that the “aromatic stability” of benzene molecules is due not only to the “delocalization” of the orbitals in their circular conjugated systems “Or” contraction “or” localization “effect of the orbits that are opposite and closely connected with each other, and the” delocalization “and” localization “of the σ-orbitals also play a very important role in Which plays more than the π-orbit is more important Effect When π-orbital ”shrinkage“ (adjustment factor increased from 1 to 1.1043) occurs to a large degree due to the decrease of ”kinetic pressure“, only a very small ”contraction“ occurs in the π orbit (the adjustment factor is changed from 1 Only increases to 1.00761), which shows the dispersed state compared with σ-orbit, which makes the π-electron retain a larger total energy, which makes the π-electron (excluding the π-orbital ”delocalization" On the other hand, the total energy of sigma-electrons is reduced more, so that the overall performance of benzene molecules has a greater stability In our opinion, this is the main reason why benzene molecules are relatively stable overall, but their π-electrons have greater liquidity.