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Chem. J. Chinese Universities ›› 1995, Vol. 16 ›› Issue (3): 419.

• Articles • Previous Articles     Next Articles

Second-Harmonic Generation form Hemicyanine Derivative Langmuir-Blodgett Monolayers Deposited with Halide Salts in the Subphase

MA Shi-Hong1, LU Xing-Ze1, HAN Kui1, ZHENG Jia-Biao1, WANG Wen-Cheng1, ZHANG Zhao-Kui2   

  1. 1. State Key Joint Laboratory for Materials Modification by Laser Electron Beams(Fudan Branch), Laboratory of Laser Physics and Optics, Fudan University, Shanghai 200433;
    2. Department of Physics, East China University of Science and Technology, Shanghai 200237
  • Received:1994-06-02 Revised:1994-09-15 Online:1995-03-24 Published:1995-03-24

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Abstract: Anew hemicyanine derivative E-N-docosyl-4-[2-(4-diethyl-aminopheny) ethenyl]pyridinium bromide(DAEP),was adopted to investigate the effects of KIin the subphase on pure and mixed DAEP monolayers by π-A, UV-Vis absorption and second harmonic generation(SHG) measurements, as well as the physical mechanisms were involved. We found that with increasing KIconcentration in the subphase,an enhancement of the effective molecular hyperpolarizabilityβwas always associated with a red-shift of the absorption peak in both pure and mixed DAEP monolayers. Charge distribution change and reduction of the excited state energy result in a second harmonic resonant effect were one of the main mechanisms responsible for the enhancement of the effective molecular hyperpolarizability in DAEP Langmuir-Blodgett monolayers.

Key words: Optical second harmonic generation, Langmuir-Blodgett monolayer, Hemicyanine derivative

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