【摘要】 为分析苯并分子C12H6的垂直共振能(VRE),建立了定域片断分子轨道(LFMO)和自然键轨道(NBO)两种基组,并在两种基组之上进行NBO能量分析和Morokum a能量分解.在NBO能量分析中,两种基组的VRE都是稳定的;而在Morokum a能量分解中,VRE的稳定性取决于基组.在NBO能量分析中,Fock矩阵的一次性对角化忽视了σ体系和π体系之间的电子耦合作用.故NBO基组和NBO能量分析方法在计算VRE时似乎都不合理.更多还原

【Abstract】 To analyze the vertical resonance energy（VRE） of C₁₂H₆,the localized fragment molecular orbital（LFMO） and the natural bond orbital（NBO） basic sets are constructed.Then,the NBO and Morokuma′s SCF energetic analysis are performed over each of them.The VRE,obtained from the NBO electronic analysis,is always unstable.But the VRE,obtained from Morokuma′s SCF energy partition,depends on the basis set.In addition,the singly diagonalized process for the Fock matrix in the NBO energetic analysis ignores the electronic coupling between σ and π systems.In a word,the NBO basic set and its energetic analysis seems to be unreasonable as far as the calculation of VRE is concerned.更多还原