Topic
Raman spectroscopy
About: Raman spectroscopy is a research topic. Over the lifetime, 122605 publications have been published within this topic receiving 2891083 citations. The topic is also known as: Raman Spectrum Analysis & spectrum Analysis, Raman.
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TL;DR: In this paper, a simple, scaleable substrate for surface-enhanced Raman spectroscopy (SERS) incorporating nanometer-scale electromigrated gaps between extended electrodes is presented.
Abstract: Single-molecule detection with chemical specificity is a powerful and much desired tool for biology, chemistry, physics, and sensing technologies. Surface-enhanced spectroscopies enable single-molecule studies, yet reliable substrates of adequate sensitivity are in short supply. We present a simple, scaleable substrate for surface-enhanced Raman spectroscopy (SERS) incorporating nanometer-scale electromigrated gaps between extended electrodes. Molecules in the nanogap active regions exhibit hallmarks of very high Raman sensitivity, including blinking and spectral diffusion. Electrodynamic simulations show plasmonic focusing, giving electromagnetic enhancements approaching those needed for single-molecule SERS.
282 citations
TL;DR: To reveal the impact of methylating the C2 position and changing the alkyl side chain length of the imidazolium a detailed assignment of the individual peaks is followed by a comparative discussion of the spectral features also considering already published work.
Abstract: Methylation of the C2 position of 1,3-dialkylimidazolium based ionic liquids disrupts the predominant hydrogen-bonding interaction between cation and anion leading to unexpected changes of the physicochemical properties. We found the viscosity of 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide [C2C1C1Im][Tf2N], for example, to be about three times higher than that of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C2C1Im][Tf2N]. In order to explain these macroscopic changes upon methylation we investigated the vibrational as well as the magnetic resonance structure of [Tf2N]− salts involving the cations 1-ethyl-3-methylimidazolium [C2C1Im]+, 1-ethyl-2,3-dimethylimidazolium [C2C1C1Im]+, 1-butyl-3-methylimidazolium [C4C1Im]+, and 1-butyl-2,3-dimethylimidazolium [C4C1C1Im]+ by means of Fourier-transform infrared (FTIR), Raman and 13C NMR as well as 1H NMR spectroscopy aiming a better microscopic understanding of the cation–anion interaction. To reveal the impact of methylating the C2 position and changing the alkyl side chain length of the imidazolium a detailed assignment of the individual peaks is followed by a comparative discussion of the spectral features also considering already published work. Our spectroscopic findings deduce electron density changes leading to changes in the position and strength of interionic interactions and reduced configurational variations. Both facts are represented on a macroscopic level by the viscosity and melting point. Therefore changes on a macroscopic level clearly express molecular alterations which in turn can be observed using spectroscopic methods as Raman, IR and NMR.
281 citations
TL;DR: Click-free imaging of the nuclear localization of an alkyne-tagged cell proliferation probe, EdU, in living cells was achieved for the first time by means of Raman microscopy, and this approach may eliminate the need for click reactions in the detection of alkynes-labeled molecules.
Abstract: Click-free imaging of the nuclear localization of an alkyne-tagged cell proliferation probe, EdU, in living cells was achieved for the first time by means of Raman microscopy. The alkyne tag shows an intense Raman band in a cellular Raman-silent region that is free of interference from endogenous molecules. This approach may eliminate the need for click reactions in the detection of alkyne-labeled molecules.
281 citations
280 citations
TL;DR: In this article, the spectral development of stimulated Raman scattering in singlemode silica fibers was studied both experimentally and by computer modeling, and the most striking feature that emerges is the rapid growth of a weak feature at 490 cm−1 at the expense of a broad band at 440 cm− 1 as pump power increases.
Abstract: The spectral development of stimulated Raman scattering in single-mode silica fibers was studied both experimentally and by computer modeling. The most striking feature that emerges is the rapid growth of a weak feature at 490 cm−1 at the expense of a broad band at 440 cm−1 as pump power increases. These experimental results are in good agreement with our numerical simulations, although neither experiments nor calculations show the spectral broadening of higher Stokes orders commonly observed with high pump powers and at infrared wavelengths. It is shown that, in general, spectral broadening from four-wave mixing should be important in the development of the stimulated Raman spectrum. However, the present experiments fall into a regime of relatively low pump powers at visible wavelengths in which four-wave mixing is negligible and the stimulated spectrum depends only on the shape of the Raman gain curve.
280 citations