Theoretical elucidation of the origin of surface-enhanced Raman spectra of PCB52 adsorbed on silver substrates

Authors

  • Wen-Xiao Pan,

    1. Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, Shandong University, Jinan, China
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  • Yong-Chao Lai,

    1. Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, Shandong University, Jinan, China
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  • Ruo-Xi Wang,

    1. Criminal Scientific and Technological Department, Shandong Police College, Jinan, China
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  • Dong-Ju Zhang,

    Corresponding author
    1. Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, Shandong University, Jinan, China
    • Correspondence to: Dongju Zhang, Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, Shandong University, Jinan, 250100, China.

      E-mail: zhangdj@sdu.edu.cn

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  • Jin-Hua Zhan

    1. Key Lab of Colloid and Interface Chemistry, Ministry of Education, Institute of Theoretical Chemistry, Shandong University, Jinan, China
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  • This article was published online on 2 January 2014. This notice is included in the online and print version to indicate that the Acknowledgements have been modified [8 January 2014].

Abstract

To better understand experimentally observed surface-enhanced Raman Scattering (SERS) of polychlorinated biphenyls (PCBs) adsorbed on nanoscaled silver substrates, a systematic theoretical study was performed by carrying out density functional theory and time-dependent density functional theory calculations. 2,2′,5,5′-tetrachlorobiphenyl (PCB52) was chosen as a model molecule of PCBs, and Agn (n = 2, 4, 6, and 10) clusters were used to mimic active sites of substrates. Calculated normal Raman spectra of PCB52–Agn (n = 2, 4, 6, and 10) complexes are analogical in profile to that of isolated PCB52 with only slightly enhanced intensity. In contrast, the corresponding SERS spectra calculated at adopted incident light are strongly enhanced, and the calculated enhancement factors are 104 ~ 105. Thus, the experimentally observed SERS phenomenon of PCBs supported on Ag substrates should correspond to the SERS spectra rather than the normal Raman spectra. The dominant enhancement in Raman intensities origins from the charge transfer resonance enhancement between the molecule and clusters. Copyright © 2014 John Wiley & Sons, Ltd.

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