Failure and Reexamination of the Raman Scattering Enhancement Factor Predicted by the Enhanced Local Electric Field in a Silver Nanorod
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- 作者：Yadong Zhou ; Yan Tian ; Shengli Zou
- 刊名：Journal of Physical Chemistry C
- 出版年：2015
- 出版时间：December 10, 2015
- 年：2015
- 卷：119
- 期：49
- 页码：27683-27687
- 全文大小：332K
- ISSN：1932-7455
文摘
The Raman scattering of a molecule will be enhanced when it is placed near a metal nanoparticle and the enhancement factor was believed to be proportional to the enhanced local electric field |E|2 at both excitation and scattering wavelengths. The original prediction was derived based on spherical particles but was popularly applied to different configurations. Using electrodynamics theory, we directly calculated the enhancement factor of the Raman scattering at scattering wavelengths when a molecule is placed near a silver nanorod. Contrary to the previous theory, we found that the correlation between the Raman scattering enhancement factor and the enhanced local electric field at scattering wavelengths completely disappeared when different modes of the rod were excited. These two factors can be different from each other by over 50 folds and even show different trends in the studied system. The calculations showed that the Raman scattering enhancement factor cannot be simply predicted using the enhanced local electric field in a complex system. The correct value should be calculated using the introduced electrodynamics model.