Kekule valence structures revisited. Innate degrees of freedom of PI-electron couplings
Kekule valence structures revisited. Innate degrees of freedom of PI-electron couplings
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发表时间：
1985
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通讯作者：
M. Randic;D. Klein
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作者：
M. Randic;D. Klein
对于单个的Kekule价结构，我们考虑CC双键的最小可能放置次数，使得Kekule结构完全确定。这个数字可以被看作是对单个Kekule价结构的特殊加权方案。或者，它的倒数表示凯库勒结构中长程有序的程度。来自单个Kekule价结构的贡献增加了一个新的结构不变量F，即与共轭系统相关的固有自由度。我们发现F与分子共振能有很好的相关性。参考文献8，图3。
For individual Kekule valence structures we consider the smallest possible number of placements of CC double bonds such that a Kekule structure is fully determined. The number may be viewed as special weighting scheme for individual Kekule valence structures. Alternatively its reciprocal indicates the degree of a long-range order in a Kekule structure. Contributions from individual Kekule valence structure add to a novel structural invariant F, the innate degree of freedom associated to a conjugated system. We find that F correlates well with the molecular resonance energy. 8 refs., 3 figs.