C_4^(2+)的几何构型和JahnTeller效应

GEOMETRY OF C_4^(2+) AND THE JAHN-TELLER EFFECT

用从头计算法QCISD 6 - 311G 得到了C2 +4 分子的 10种不同的几何构型 ,其中包括Cs,C∞v,C2v,D2h,D∞h,D4h,D2d,C3v等不同的构型 .计算表明C2 +4 的Td 构型不能稳定存在 ,详细讨论了Td 构型的Jahn Teller效应 .讨论结果显示它们的各种畸变方式都符合群的分解原理 ,从而证明了C2 +4 分子的Td 构型的Jahn Teller效应非常明显 .D4h构型也存在Jahn Teller效应 .

stable geometrical configurations of electronic states for C 2+ 4 are found with QCISD/6-311G * method. These configurations are C s, C ∞v , C 2v , D 2h , D ∞h , D 4h , D 2d and C 3v , etc. The Jahn-Teller distortions from the configurations C 2+ 4(T d) and C 2+ 4 (D 4h ) exist. The analysis of the relationships among these various geometrical configurations, based on the Jahn-Teller effect, vibronic interaction and the resolution of group representations, is in agreement with the calculated results. The most stable electronic state of C 2+ 4 is 3A″ of the planar C s configuration.