Frequency-Resolved Nanoscale Chemical Imaging of 4,4鈥?Dimercaptostilbene on Silver
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- 作者：Patrick Z. El-Khoury ; Tyler W. Ueltschi ; Amanda L. Mifflin ; Dehong Hu ; Wayne P. Hess
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：November 26, 2014
- 年：2014
- 卷：118
- 期：47
- 页码：27525-27530
- 全文大小：479K
- ISSN：1932-7455
文摘
Nonresonant tip-enhanced Raman (TERS) images of 4,4鈥?dimercaptostilbene (DMS) molecules adsorbed on silver reveal that different vibrational resonances of the molecules are optimally enhanced at different sites of the metal surface. The recorded images map the interaction between vibrational-mode-dependent polarizability tensors of DMS and enhanced electromagnetic fields at a plasmonic tip鈥搒urface nanojunction. TERS images also provide insights into specific molecule鈥搈etal interactions. Namely, by virtue of the symmetry (C2h) of the molecular reporter specifically selected for this study, we demonstrate how non-totally symmetric vibrational modes of DMS (bu modes) map differences in vibronic coupling strength across the metal surface. In effect, each pixel in the recorded TERS images reports on the distinct local environments in which the various probed molecules reside. We illustrate the concept.