Surface Enhanced Raman field enhancement

Nie S and Emory S R 1997 Near-field surface-enhanced Raman spectroscopy on single silver nanoparticles Anal. Chem. 69 2631-5... 

Zeisel D, Deckert V, Zenobi R and Vo-Dinh T 1998 Near-field surface-enhanced Raman spectroscopy of dye molecules adsorbed on silver island films Chem. Phys. Lett. 283 381... 

The last problem of this series concerns femtosecond laser ablation from gold nanoparticles [87]. In this process, solid material transforms into a volatile phase initiated by rapid deposition of energy. This ablation is nonthermal in nature. Material ejection is induced by the enhancement of the electric field close to the curved nanoparticle surface. This ablation is achievable for laser excitation powers far below the onset of general catastrophic material deterioration, such as plasma formation or laser-induced explosive boiling. Anisotropy in the ablation pattern was observed. It coincides with a reduction of the surface barrier from water vaporization and particle melting. This effect limits any high-power manipulation of nanostructured surfaces such as surface-enhanced Raman measurements or plasmonics with femtosecond pulses. 

M. (2006) Ahgned silver nanorod arrays for surface-enhanced Raman scattering. Nanotechnology, 17, 2(>70-2(>74, (b) Lu, Y, Liu, G.L., Kim, J., Mejia, Y.X. and Lee, L.P. (2005) Nanophotonic crescent moon structures with sharp edge for ultrasensitive biomolecular detection by local electromagnetic field enhancement effect Nano Letters, 5, 119-124 ... 

Enhanced Optical Fields in Spherical Nanoparticle Assemblies and Surface Enhanced Raman Scattering... 

We also tried measurements to demonstrate that hot spots make significant contributions to surface enhanced Raman scattering [34]. For this purpose, the sample of nanoparticie assembly was doped with Raman active molecules by a spincoating method, and near-field excited Raman scattering from the sample was recorded. We adopted Rhodamine 6G dye as a Raman active material, which is... 

To summarize, we have shown here that enhanced electric-field distribution in metal nanoparticle assemblies can be visualized on the nanoscale by a near-field two-photon excitation imaging method. By combining this method and near-field Raman imaging, we have clearly demonstrated that hot spots in noble metal nanoparticle assemblies make a major contribution to surface enhanced Raman scattering. 

Imura, K., Okamoto, H., Hossain, M. K. andKitajima, M. (2006) Near-field imaging of surface-enhanced Raman active sites in aggregated gold nanoparticles. Chem. Lett., 35, 78-79. 

Interfacial water molecules play important roles in many physical, chemical and biological processes. A molecular-level understanding of the structural arrangement of water molecules at electrode/electrolyte solution interfaces is one of the most important issues in electrochemistry. The presence of oriented water molecules, induced by interactions between water dipoles and electrode and by the strong electric field within the double layer has been proposed [39-41]. It has also been proposed that water molecules are present at electrode surfaces in the form of clusters [42, 43]. Despite the numerous studies on the structure of water at metal electrode surfaces using various techniques such as surface enhanced Raman spectroscopy [44, 45], surface infrared spectroscopy [46, 47[, surface enhanced infrared spectroscopy [7, 8] and X-ray diffraction [48, 49[, the exact nature of the structure of water at an electrode/solution interface is still not fully understood. 

Deckert V., Zeisel D., Zenobi R., Vo-Dinh T., Near-field surface enhanced Raman imaging of dye-labeled DNA with 100-nm resolution, Anal. Chem. 1998 70 2646-2650. 

Kneipp, K., Kneipp, H., and Kneipp, J., 2006. Surface-enhanced Raman scattering in local optical fields of silver and gold nanoaggregates— From single-molecule Raman spectroscopy to ultrasensitive probing in live cells. Acc. Chem. Res. 39 443-50. 

Section II will discuss the basic phenomena of inelastic tunneling from the viewpoint of the experimentalist. Section III will treat peak shapes, shifts, and widths. Section IV will deal with intensities and selection rules in IETS. Finally, Section V includes some recent applications of IETS to the fields of chemisorption and catalysis, and to the at first glance unrelated field of surface enhanced Raman spectroscopy. 

Surface enhanced Raman spectroscopy (SERS) experiments on silver and gold nanoclusters have demonstrated large enhancement levels and field confinement of 5 nm or less for various samples such as single-walled carbon nanotubes.1 However, the locations of these conditions cannot be controlled but are instead determined by the specific nanostructures used. That is, the target molecules have... 

Figure 10.1. Comparison of normal (top) and surface-enhanced (bottom) Raman scattering. The top panel shows the conversion of incident laser light of intensity /(vl) into Stokes scattered light /NRS, which is proportional to the Raman cross section and the number of target molecules N in the probed volume. In the bottom panel

Duyne and co-workers estimated enhancement factors on the order of 105 to 106 for pyridine on rough silver electrodes. The value was obtained from a comparison between surface-enhanced and normal bulk Raman signals from pyridine by taking into account the different number of molecules on the electrode and in solution. The size of the enhancement was found to correlate with the electrode roughness, indicating that enhancement occurs via a strong electromagnetic field. On the other hand, the dependence of the... 

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