High first-hyperpolarizabilities of thiobarbituric acid derivative-based donor-π-acceptor nonlinear optical-phores: Multiple theoretical investigations of substituents and conjugated bridges effect |
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Authors: | Yidan Liu Yizhong Yuan Xiaohui Tian Jianyong Yuan Jinyu Sun |
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Institution: | Key Laboratory for Ultrafine Materials of Ministry of Education and Shanghai Key Laboratory of Advanced Polymeric Materials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, China |
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Abstract: | A number of compounds including thiobarbituric acid derivative-based acceptor unit and diverse donor moieties along with two types of π-conjugated bridges have been constructed to aid in the design of the superior nonlinear optical (NLO) materials. The effect of varying the donor and bridge parts of this donor-bridge-acceptor system was analyzed in terms of structural and opto-electronic parameters such as bond length alternation and ultraviolet-visible absorption spectra. Various functionals with aug-cc-pVDZ basis set including B3LYP, PBE0, PBE38, BMK, CAM-B3LYP, and ωB97XD were employed to calculate the static and dynamic first-hyperpolarizabilities, and also the linear polarizabilities. Furthermore, the variation of the static first-hyperpolarizabilities has been explained satisfactorily in the light of the sum-over-states method and two-level model. The comprehensive study indicates that the coplanar compound D-5 with the low electronic absorption energy, strongest oscillator strength paired with the largest ground, and excited state dipole moment difference generates a dramatical increase in its static and dynamic first-hyperpolarizabilities, which would be the most worthwhile target for development as the NLO-phores. |
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Keywords: | density functional theory donor-bridge-acceptor first-hyperpolarizability nonlinear optical properties sum-over-states method |
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