An External Electric Field Manipulated Second-Order Nonlinear Optical Switch of an Electride Molecule: A Long-Range Electron Transfer Forms a Lone Excess Electron Pair and Quenches Singlet Diradical

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• 作者：Jia-Jun Wang ; Zhong-Jun Zhou ; Hui-Min He ; Di Wu ; Ying Li ; Zhi-Ru Li ; Hong-Xing Zhang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：June 30, 2016
• 年：2016
• 卷：120
• 期：25
• 页码：13656-13666
• 全文大小：618K
• 年卷期：0
• ISSN：1932-7455

文摘

An electride molecule e^–···K(1)⁺···calix[4]pyrrole···K(2)⁺···e^– as an external electric field (F) manipulated nonlinear optical (NLO) switch is designed theoretically for the first time. As this molecule is an unusual singlet diradical electride molecule with two easily driven excess electrons (by electric field) at two opposite ends of the molecule, a novel switching mechanism of electronic structure isomerization emerges as a distinctive nonbonding evolution in the electride molecule. A small electric field driving leads to a long-range excess electron transfer from one side K(1) through the middle calix[4]pyrrole to the other side K(2), forms a lone excess electron pair of s-type rather than a single bond, and quenches the singlet diradical. Meanwhile, the molecular electronic structure becomes K(1)⁺···calix[4]pyrrole···K(2)⁺···2e^–. Therefore, the small electric field driving brings a very high static first hyperpolarizability (β₀) contrast from 0 (F = 0, Off form) to 4.060 × 10⁵ au (F = a small nonzero value of 5 × 10^–4 au, On form). Notably, under the electric field of 30 × 10^–4 au, β₀ reaches the largest value of 3.147 × 10⁶ au and the molecule displays the most optimal NLO switching behavior. Furthermore, we consider also that 4H atoms of calix[4]pyrrole are substituted with 4F and 2Be atoms, respectively; then the 2Be and 4F substitution effects on the NLO switch in electride molecules are exhibited. This work opens a new research field of an electric field manipulated NLO switch of electride molecules.