Direct visual evidence for the chemical mechanism of surface-enhanced resonance Raman scattering via charge transfer

Authors

  • Mengtao Sun,

    Corresponding author
    1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China
    • Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China.
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  • Shasha Liu,

    1. School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, P. R. China
    2. Department of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
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  • Maodu Chen,

    1. School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, P. R. China
    2. Department of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China
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  • Hongxing Xu

    1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China
    2. Division of Solid State Physics, Lund University, Lund 22100, Sweden
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Abstract

We describe the chemical and electromagnetic enhancements of surface-enhanced resonance Raman scattering (SERRS) for the pyridine molecule absorbed on silver clusters, in which different incident wavelength regions are dominated by different enhancement mechanisms. Through visualization we theoretically investigate the charge transfer (CT) between the molecule and the metal cluster, and the charge redistribution (CR) within the metal on the electronic intracluster collective oscillation excitation (EICOE). The CT between the metal and the molecule in the molecule–metal complex is considered as an evidence for chemical enhancement to SERRS. CR within the metal on EICOE is considered as an evidence for the electromagnetic enhancement by collective plasmons. For the incident wavelength from 300 to 1000 nm, the visualized method of charge difference density can classify the different wavelength regions for chemical and electromagnetic enhancement, which are consistent with the formal fragmented experimental studies. Copyright © 2008 John Wiley & Sons, Ltd.

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