Surface-enhanced resonance Raman scattering (SERRS) has been expected to be a highly-sensitive tool for structural analysis of molecules that are adsorbed on a metal surface. Indeed, SERRS enables us to identify molecular vibrations even under the single-molecule level. It is widely accepted that both electromagnetic (EM) and chemical mechanisms contribute to SERRS. There is no doubt that EM fields that are coupled with plasmon mainly contribute to large enhancement of Raman scattering, because recent calculations of EM fields at inter-particle junctions and at sharp edges of noble metal nanoaggregates well predict enhancement of Raman scattering by a factor of 108 to 1014. We have already identified that optimum polarization, spectral maxima, and Q factors of plasmon resonance are all essentials of large enhancement of Raman scattering. However, only EM mechanism cannot provide reasons why all kinds of molecules adsorbed on inter-particle junctions and sharp edges do not always generate SERRS activities. For example, we do not observed an enhanced Raman signal of water even from Ag nanoaggregates in an aqueous solution. Such questions strongly motivate us to consider that chemical interaction between molecules and Ag surfaces contributes to a large enhancement of Raman scattering. Thus, it is important to investigate chemical interaction between SERRS-active molecules and metal surfaces to explore a SERRS-chemical mechanism.
|Title of host publication||Nano Biophotonics: Science and Technology|
|Subtitle of host publication||Proceedings of the 3rd International Nanophotonics Symposium Handai, July 6-8th 2006, Suita Campus of Osaka University, Osaka, Japan|
|Editors||Hiroshi Masuhara, Satoshi Kawata, Fumio Tokunaga|
|Place of Publication||Amsterdam Netherlands|
|Number of pages||14|
|ISBN (Print)||9780444528780, 0444528784|
|Publication status||Published - 2007|