Intramolecular Insight into Adsorbate鈥揝ubstrate Interactions via Low-Temperature, Ultrahigh-Vacuum Tip-Enhanced Raman Spectroscopy

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• 作者：Jordan M. Klingsporn ; Nan Jiang ; Eric A. Pozzi ; Matthew D. Sonntag ; Dhabih Chulhai ; Tamar Seideman ; Lasse Jensen ; Mark C. Hersam ; Richard P. Van Duyne
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：March 12, 2014
• 年：2014
• 卷：136
• 期：10
• 页码：3881-3887
• 全文大小：409K
• 年卷期：v.136,no.10(March 12, 2014)
• ISSN：1520-5126

文摘

Tip-enhanced Raman spectroscopy (TERS) provides chemical information for adsorbates with nanoscale spatial resolution, single-molecule sensitivity, and, when combined with scanning tunneling microscopy (STM), 脜ngstrom-scale topographic resolution. Performing TERS under ultrahigh-vacuum conditions allows pristine and atomically smooth surfaces to be maintained, while liquid He cooling minimizes surface diffusion of adsorbates across the solid surface, allowing direct STM imaging. Low-temperature TER (LT-TER) spectra differ from room-temperature TER (RT-TER), RT surface-enhanced Raman (SER), and LT-SER spectra because the vibrational lines are narrowed and shifted, revealing additional chemical information about adsorbate鈥搒ubstrate interactions. As an example, we present LT-TER spectra for the rhodamine 6G (R6G)/Ag(111) system that exhibit such unique spectral shifts. The high spectral resolution of LT-TERS provides intramolecular insight in that the shifted modes are associated with the ethylamine moiety of R6G. LT-TERS is a promising approach for unraveling the intricacies of adsorbate鈥搒ubstrate interactions that are inaccessible by other means.