Structural effects on the low cubic hyperpolarizability of C60: A scaling of conjugation in three-dimensional curvature of π-conjugation systems
✍ Scribed by Ying-Ting Lin; Shyi-Long Lee
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 598 KB
- Volume
- 75
- Category
- Article
- ISSN
- 0020-7608
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✦ Synopsis
The semiempirical AM1-calculated cubic hyperpolarizability is found to Ž be surprisingly low in C , which is in agreement with recent experimental results. In 60 the past, 10 orders of magnitude discrepancy has existed in the literature for the cubic . hyperpolarizabilities of C . Comparing some selected groups of polyaromatic 60 hydrocarbons, we show that linearity and planarity are two dominating factors in the second hyperpolarizability in polyaromatic rings. Therefore, the observations that aromatic rings on C lose their linearity and planarity account for the low second 60 hyperpolarizability. Furthermore, the planarity defined mathematically can be served as a scale of conjugation in -conjugation systems. By using biphenyl as a reference, the cubic hyperpolarizability of C can be estimated by the scaling of conjugation. ᮊ