Theoretical investigation of the structures, stabilities, and NLO responses of calcium-doped pyridazine: Alkaline-earth-based alkaline salt electrides

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• 作者：Yin-Feng Wang ; Jiangen Huang ; Li Jia ; Guangpei Zhou
• 关键词：Alkaline-earth-based electride ; First hyperpolarizability ; Doping effect ; Alkaline salt effect ; Pyridazine
• 刊名：Journal of Molecular Graphics and Modelling
• 出版年：February, 2014
• 年：2014
• 卷：47
• 期：Complete
• 页码：77-82
• 全文大小：1065 K

文摘

Currently, whether alkaline-earth-doped compounds with electride characteristics are novel candidates for high-performance nonlinear optical (NLO) materials is unknown. In this paper, using quantum chemical computations, we show that: when doping calcium atoms into a family of alkaline-substituted pyridazines, alkaline-earth-based alkaline salt electrides M-H₃C₄N₂鈰疌a (MH, Li, and K) with distended excess electron clouds are formed. Interestingly, from the triplet to the singlet state, the chemical valence of calcium atom changes from +1 to 0, and the dipole moment direction (渭₀) of the molecule reverses for each M-H₃C₄N₂鈰疌a. Changing pyridazine from without (H₄C₄N₂鈰疌a) to with one alkaline substituent (M-H₃C₄N₂鈰疌a, MLi and K), the ground state changes from the triplet to the singlet state. The alkaline earth metal doping effect (electride effect) and alkaline salt effect on the static first hyperpolarizabilities (尾₀) demonstrates that (1) the 尾₀ value is increased approximately 1371-fold from 2 (pyridazine, H₄C₄N₂) to 2745 au (Ca-doped pyridazine, H₄C₄N₂鈰疌a), (2) the 尾₀ value is increased approximately 1146-fold from 2 in pyridazine (H₄C₄N₂) to 2294 au in an Li-substituted pyridazine (Li-H₃C₄N₂), and (3) the 尾₀ value is increased 324-(MLi) and 106-(MK) fold from 826 (MLi) and 2294 au (MK) to 268,679 (MLi) and 245,878 au (MK), respectively, from the alkalized pyridazine (M-H₃C₄N₂) to the Ca-doped pyridazine (M-H₃C₄N₂鈰疌a). These results may provide a new means for designing high-performance NLO materials.