Designing a new class of excess electron compounds with unique electronic structures and extremely large non-linear optical responses. (7th April 2020) - Li, Xiang-Hui
Abstract : New Ca + -1 -M′ − (M′ = Li, Na, and K) compounds with typical alkalide features and electride-like characteristics have been obtained. Abstract : An intriguing class of excess electron compounds with unique electronic structures was obtained on the basis of a facially polarized molecule, namely, all- cis -1, 2, 3, 4, 5, 6-hexafluorocyclohexane (1 ). By doping two different faces of this Janus molecule with an alkaline earth atom and an alkali-metal atom, a series of M-1 -M′ (M = Be, Mg, and Ca; M′ = Li, Na, and K) compounds were first constructed. The calculated results show that unlike Be and Mg, one 4s electron of Ca in Ca + -1 -M′ − (M′ = Li, Na, and K) can be transferred to the upper alkali metal atom, thus forming an alkali metal anion, while the remaining 4s electron of Ca is pushed away from Ca +, yielding localized electrons around it by the instinctive facial polarization of 1 or with the assistance of oriented external electric fields (OEEFs). Interestingly, these novel compounds exhibit extremely large first hyperpolarizabilities ( β 0 ) in the range of 9.94 × 10 5 –1.81 × 10 6 a.u. and high stability. Thus, this work can provide first members simultaneously containing typical alkalide features and electride-like characteristics to further enrich the family of excess electron compounds and offer novel candidates for NLO materials with high performance.