Download or read book Surface Enhanced Raman Scattering for Redox Active Adsorbates Pentaammineosmium III II and Pentaammineruthenium II Containing Nitrogen Heterocycle Ligands written by S. Farquharson and published by . This book was released on 1984 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-Enhanced Raman Scattering (SERS) for pentaammineosmium (III) and pentaammineruthenium(II) containing pyridine (py), pyrazine (pz), or 4,4'-bipyridine (bpy) ligands adsorbed at the silver-aqueous interface has been examined as a function of electrode potential to explore vibrational changes associated with electron transfer involving simple adsorbates. SERS was observed for the pyridine complexes despite their lack of an unshared electron pair for surface binding, although more intense spectra were obtained for the pyrzine and bipyridine complexes which contain a remote nitrogen lone pair. SER vibrational bands for metal-ligand and internal ammine modes were observed in addition to those due to heterocycle ring modes. Marked shifts were observed in the frequency of several, vibrational bands for adsorbed Os(NH3)5py and Os(NH3)5pz as the electrode potential was made more negative that are consistent with the reduction fo Os(III) to Os(II). The potential-dependent concentrations of adsorbed Os(III) and Os(II) as determined using SERS are in good agreement with those obtained from rapid cyclic voltammetry. The bulk-phase Raman spectra exhibit resonance enhancement.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1984 with total page 1200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Enhanced Raman Spectroscopy of Pentaammineosmium III II and Pentaammineruthernium II Containing Pyridine Pyrazine Or 4 4 Bipyridine Ligands at Silver Electrodes Vibrational Assignments written by S. Farquharson and published by . This book was released on 1984 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed vibrational assignments are described for Surface Enhanced Raman (SER) spectra of pentaamminoeosmium(III), (II) and pentaammineruthenium(II) containing pyridine (py), pyrazine (pz), and 4,4'-bipyridine (bpy) ligands adsorbed at the silver-aqueous interface. The assignments are based on group symmetry analysis, deuteration effects, and by comparison with corresponding normal Raman and infrared spectra for the solid-phase complexes and surface and bulk Raman spectra for the corresponding free ligands. Most bands present in the normal Raman and/or infrared spectra also appear in the SER spectra. This results from the high intensity of the SER spectra along with the relaxation of vibrational selection rules for adsorbed molecules. The appearance of intense SER spectra for Os(NH3)5py(III)/(II) and RuII(NH3)5py is noteworthy since unlike free pyridine, these lack an available nitrogen for surface coordination. The results illustrate the virtues of electrochemical SER spectroscopy for examining the detailed vibrational properties of coordination compounds, including those in oxidation states (such as Os(II) here) that are difficult to obtain pure in bulk media. (Author).
Download or read book Government Reports Annual Index written by and published by . This book was released on 1984 with total page 1302 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1984-08 with total page 1208 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Enhanced Raman Scattering New Theoretical Approaches Materials and Strategies written by Ivano Alessandri and published by Frontiers Media SA. This book was released on 2020-03-25 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Enhanced Raman Scattering written by Richard Chang and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the course of the development of surface science, advances have been identified with the introduction of new diagnostic probes for analytical characterization of the adsorbates and microscopic structure of surfaces and interfaces. Among the most recently de veloped techniques, and one around which a storm of controversy has developed, is what has now been earmarked as surface enhanced Raman scattering (SERS). Within this phenomenon, molecules adsorbed onto metal surfaces under certain conditions exhibit an anomalously large interaction cross section for the Raman effect. This makes it possible to observe the detailed vibrational signature of the adsorbate in the ambient phase with an energy resolution much higher than that which is presently available in electron energy loss spectroscopy and when the surface is in contact with a much larger amount of material than that which can be tolerated in infrared absorption experiments. The ability to perform vibrational spectroscopy under these conditions would lead to a new understanding about the chemical identity, geome try, and bonding of adsorbed material at a level previously unacces sible. It is for these reasons that the last few years have brought an explosion of activity surrounding the exploitation of SERS. The search for the origines) of the anomalous enhancement has given rise to a research sub-activity of its own. Efforts to explain the en hancement have led to an increased understanding of the whole range of phenomena associated with the interaction of photons with adsor bates and metal surfaces.
Download or read book Surface Enhanced Raman Scattering written by Katrin Kneipp and published by Springer Science & Business Media. This book was released on 2006-06-21 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Almost 30 years after the first reports on surface-enhanced Raman signals, the phenomenon of surface-enhanced Raman scattering (SERS) is now well established. SERS gained particular interest after single-molecule Raman spectroscopy had been demonstrated. This book summarizes and discusses present theoretical approaches that explain the phenomenon of SERS and reports on new and exciting experiments and applications of the fascinating spectroscopic effect.
Download or read book Observation of a Reversible Adsorbed Redox Couple Using Surface Enhanced Raman Scattering Pentaamminepyridineosmium III II at Silver Electrodes written by Stuart Farquharson and published by . This book was released on 1983 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-enhanced Raman scattering (SERS) has been observed for pentaamminepyridineosmium(III) adsorbed at a silver electrode as a function of electrode potential in order to examine the molecular vibrational changes of electrode potential in order to examine the molecular vibrational changes accompanying electron transfer involving a simple surface-bound redox couple. Noticeable alterations in the intensity and frequency of several vibrational bands involving osmium-ligand and pyridine ring modes were observed as the electrode potential was made more negative which are consistent with a variation of the osmium oxidation state from III to II. The effective formal potential for the adsorbed Os(III)/(II) couple determined from SERS, ca -630 mV vs sce, is in reasonable agreement with that obtained from rapid cyclic voltammetry, illustrating the value of SERS for monitoring electron-transfer processes at metal surfaces. (Author).
Download or read book Surface Enhanced Raman Scattering written by Richard Chang and published by . This book was released on 2014-01-15 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface Enhanced Raman Spectroscopy of Electrochemically Characterized Interfaces Transition Metal Isothiocyanate Adsorbates at Silver Adsorbates written by M. A. Tadayyoni and published by . This book was released on 1984 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-enhanced Raman (SER) spectra have been obtained at the silver-aqueous interface for nine Cr III, Co III, Ru II, and Rh III ammine or ethylenediamine complexes containing one or more thiocyanates as surface bridging groups. These complexes provide stereochemically well-defined adsorbates having at least one sulfur surface binding site but with electronic properties that differ substantially from thiocyanate itself. The dependence of the SER spectra were examined in each case over a potential range where the complexes are stable with respect to reduction or oxidation, and where the adsorbate coverage remained close to a monolayer. The adsorbate coverage could be evaluated in several cases from the faradaic charge required for one-electron reduction. SER spectra were obtained using a spectrograph-optical multichannel analyzer (OMA) as well as a conventional scanning spectrometer. This enabled the rapid reversible component of the SERS potential dependence to be separated from the irreversible signal decay associated with surface rearrangement. SERS bands due to metal ammine and internal ammine vibrations were observed in addition to those associated with internal thiocyanate and ligand-surface vibrations.
Download or read book Surface Enhanced Raman Spectroscopy for Biophysical Applications written by Claudia Fasolato and published by Springer. This book was released on 2018-12-05 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book explores the phenomenon of surface-enhanced Raman scattering (SERS), the huge amplification of Raman signal from molecules in the proximity of a metallic nanostructured surface, allowing readers to gain an in-depth understanding of the mechanisms affecting the spectroscopic response of SERS-active systems for effective applications. SERS spectroscopy is an ultrasensitive analytical technique with great potential for applications in the field of biophysics and nanomedicine. As examples, the author presents the design of nanocolloid-based SERS-active substrates for molecular sensing and of a folate-based SERS-active nanosensor capable of selectively interacting with cancer cells, enabling cancer diagnostics and therapy at the single-cell level. The author also suggests novel paths for the systematization of the SERS nanosystem design and experimental protocols to maximize sensitivity and reproducibility, which is essential when real-world biomedical applications are the goal of the study. With a combined approach, both fundamental and applied, and a detailed analysis of the state of the art, this book provides a valuable overview both for students new to SERS spectroscopy and for experts in the field.
Download or read book Surface Enhanced Raman Scattering written by Zhong-Qun Tian and published by John Wiley & Sons Incorporated. This book was released on 2010-06-14 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-Enhanced Raman Spectroscopy: Principles, Experiments, and Applications is a comprehensive, up to date, and balanced treatment of the theoretical and practical aspects of Surface-Enhanced Raman Scattering (SERS), a useful branch of spectroscopy for several areas of science. This book describes the basic principles of SERS, including SERS mechanisms, performing SERS measurements, and interpreting data. Also emphasized are applications in electrochemistry; catalysis; surface processing and corrosion; Self-Assemble-Layer and L-B Films; polymer science; biology; medicine and drug analysis; sensors; fuel cells; forensics; and archaeology. It is an essential guide for student and professional analytical chemists.
Download or read book The Application of SERS Surface Enhanced Raman Scattering to Study Surface Oxidation Reactions of Phosphonates written by Paul B. Dorain and published by . This book was released on 1988 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface enhanced Raman scattering has developed into an important spectroscopic tool in the identification of adsorbates on silver, copper, or gold under in situ conditions. This paper describes the first use of this technique to study the kinetics of surface enhanced catalyzed chemical reactions. The reaction of NO2 gas with Ag powder is shown to proceed through the formation of AgNO2 which autocatalytically decomposes into AgNO3, NO, and free Ag which forms Ag microstructures. Recent experiments to elucidate the reactions of DMMP at these catalytically active sites show that H2PO4 and HPO4 are formed on the surface at room temperature. The use of dynamically produced active Ag sites as active filters for phosphonates is discussed. Keywords: Surface Enhanced Raman Scattering (SERS), Phosphonates, Kinetics, Catalysis.
Download or read book Surface Enhanced Raman Spectroscopy of Electrochemically Characterized Interfaces Relations Between Raman Scattering Intensity and Surface Coverage for Simple Anionic Adsorbates written by M. J. Weaver and published by . This book was released on 1983 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface-Enhanced Raman Scattering (SERS) obtained as a function of electrode potential for chloride, bromide, iodide, thiocyanate, azide, and cyanide adsorbed at roughened silver electrodes are compared with corresponding surface concentration-potential data extracted from differential capacitance measurements in order to examine the relation between SERS and surface coverage for these structurally simple adsorbates. After generating SERS by means of an oxidation-reduction cycle, it was found that altering the potential to a more negative value, where the adsorbate coverage fell below a monolayer, corresponded closely in most cases to the onset of a potential-dependent decay in the SERS intensity. Monitoring the potential dependence of the Raman intensity with an Optical Multi-channel Analyzer as well as with a conventional scanning spectrometer allowed a rapid reversible component of the potential dependence to be separated from an additional irreversible signal decay associated with the loss of Raman-active sites. The present results suggest that the adsorption energetics of the Raman-active surface sites do not differ substantially from those for the sites occupied by the majority of the adsorbate.
Download or read book Surface Enhanced Raman Scattering written by Ujjal Kumar Sur and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The steady and fast development of surface and interfacial science have set up innovative openings for new diagnostic probes for analytical characterization of the adsorbates and determination of the microscopic structure of surfaces and interfaces. Regrettably Raman spectroscopy, being a weak scattering surface phenomenon, had seized no part in it, until the discovery and development of Surface Enhanced Raman Scattering (SERS) in the early 1970's that has opened up broad research fields both in the physics and chemistry of interfaces. The discovery of SERS by Fleischmann and coworkers in 1974 at the University of Southampton, United Kingdom is closely connected with the electrochemical systems. They reported an extraordinary million-fold enhancement of weak Raman signal from pyridine molecules adsorbed onto electrochemically roughened silver electrode compared to that from free molecules in liquid environment. In early 1976, Richard P. Van Duyne and David Jeanmaire at Northwestern University observed the effect and in early 1977, M. G. Albrecht and J. A. Creighton reported similar observation. This review article deals with the development of SERS research with special importance is given to the fabrication of various SERS-active substrates, mechanism of SERS effect and its various potential applications ranging from sensors to biomedical applications.
