期刊
CHEMICAL PHYSICS
卷 343, 期 1, 页码 83-99出版社
ELSEVIER
DOI: 10.1016/j.chemphys.2007.10.033
关键词
NIR FT-Raman; FT-IR; non-linear optics; second harmonic generation; density functional theory; intramolecular charge transfer (ICT); planar conformations; frontier orbitals; HOMO-LUMO energy gap
A comprehensive investigation on the intramolecular charge transfer (ICT) of an efficient pi-conjugated potential push-pull NLO chromophore, 4-[N,N-dimethylamino]-4'-nitro stilbene (DANS), from a strong electron-donor group (dimethylamino-N(CH3)(2)) to a strong electron-acceptor group (nitro-NO2) through the pi-conjugated bridge (trans-stilbene) has been carried out from their vibrational spectra. The NIR FT-Raman and FT-IR spectra supported by the density functional theory (DFT) quantum chemical computations have been employed to analyze the effects of intramolecular charge transfer on the geometries and the vibrational modes contributing to the linear electro-optic effect of the organic NLO material. It has been observed that the changes in the endocyclic and exocyclic angles result from the charge-transfer interaction of the phenyl ring and the amino group in the electron-donor side of the NLO chromophore. The strongest vibrational modes contributing to the electro-optic effect have been identified and examined from the concurrent IR and Raman activation of v(C = C/C-C) mode, ring C = C stretching modes, in-plane deformation modes, nitro modes and the umbrella mode of methyl groups. Furthermore, the splitting of the vinyl stretching modes and the electronic effects such as hyperconjugation and back-donation on the methyl hydrogen atoms causing the decrease of stretching frequencies and infrared intensities have also been analyzed ill detail. The effect of frontier orbitals transition of electron density transfer and the influence of planarity between the phenyl rings of the stilbene moiety on the first hyperpolarizability have also been discussed. (C) 2007 Elsevier B.V. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据