摘要
用INDO系列方法对C78(C2V)的等电子体C77N+的所有21种可能异构体进行系统的理论研究.研究结果表明,最稳定异构体是由C78(C2V)沿Y方向椭球短轴所穿过的C(78)-C(73)键上的原子C(78)被N+取代所形成,椭球长轴附近的原子被取代所形成的异构体能量较低,取代位置附近易成为进一步反应的中心.用INDO/SCI方法计算了C77N+电子光谱,表明其吸收峰与C78(C2V)相比发生红移,对特征吸收峰进行了理论指认,讨论吸收峰红移的原因.
All of the possible 21 isomers for C77 N^ ＋ , an isoelectronic molecule of C7s, were investigated by the INDO methods based on C78 （C2v）. It indicates from optimization that the most stable isomer is that the nitrogen atom substitutes C （78） located at the C （78）-C （73） bond passed through by the Y shortest axis and the atoms near the Z longest axis are also easy to substitute, whereas the atoms near the X shortest axis are relatively difficult to substitute. At the same time, C78 was compressed a little and ready to perform the further reaction to form C77 NR at the location of substitution. Electronic spectra of C77 N ^＋ were calculated by INDO/SCI method and electronic transition was theoretically assigned. The red-shift of absorption peaks for electronic spectra of C77 N ^＋ took place compared with that of C78 （ C2v ） because of its narrower LUMO-HOMO energy gap. There are great differences in characteristic absorptions among C77 N ^＋ isomers, which can be considered as evidence of the formation for each isomer.
