Infrared spectroscopy surfaced-enhanced

A related effect has been described for IR spectroscopy - Surface Enhanced Infrared Absorption spectroscopy (SEIRA). However, as the enhancement factors are significantly lower than for SERS and both the required metal particle size and the activation distance between the target molecule and the particle are more than one order of magnitude smaller, no practically applicable SEIRA sensors have been demonstrated up to now. 

In addition to the indirect experimental evidence coming from work function measurements, information about water orientation at metal surfaces is beginning to emerge from recent applications of a number of in situ vibrational spectroscopic techniques. Infrared reflection-absorption spectroscopy, surface-enhanced Raman scattering, and second harmonic generation have been used to investigate the structure of water at different metal surfaces, but the pictures emerging from all these studies are not always consistent, partially because of surface modification and chemical adsorption, which complicate the analysis. 

Sampling in surface-enhanced Raman and infrared spectroscopy is intimately linked to the optical enhancement induced by arrays and fractals of hot metal particles, primarily of silver and gold. The key to both techniques is preparation of the metal particles either in a suspension or as architectures on the surface of substrates. We will therefore detail the preparation and self-assembly methods used to obtain films, sols, and arrayed architectures coupled with the methods of adsorbing the species of interest on them to obtain optimal enhancement of the Raman and infrared signatures. Surface-enhanced Raman spectroscopy (SERS) has been more widely used and studied because of the relative ease of the sampling process and the ready availability of lasers in the visible range of the optical spectrum. Surface-enhanced infrared spectroscopy (SEIRA) using attenuated total reflection coupled to Fourier transform infrared spectroscopy, on the other hand, is an attractive alternative to SERS but has yet to be widely applied in analytical chemistry. 

These surface spectroscopies can be augmented by surface infrared, NMR, surface-enhanced Raman spectroscopy (SERS), etc. A surface variant of infrared spectroscopy is based on total internal reflection and can be applied for adsorbents which are transparent for the radiation under study. The light beam enters through the sorbent and reflects at the interface. As discussed in sec. 

This article provides some general remarks on detection requirements for FIA and related techniques and outlines the basic features of the most commonly used detection principles, including optical methods (namely, ultraviolet (UV)-visible spectrophotometry, spectrofluorimetry, chemiluminescence (CL), infrared (IR) spectroscopy, and atomic absorption/emission spectrometry) and electrochemical techniques such as potentiometry, amperometry, voltammetry, and stripping analysis methods. Very few flowing stream applications involve other detection techniques. In this respect, measurement of physical properties such as the refractive index, surface tension, and optical rotation, as well as the a-, //-, or y-emission of radionuclides, should be underlined. Piezoelectric quartz crystal detectors, thermal lens spectroscopy, photoacoustic spectroscopy, surface-enhanced Raman spectroscopy, and conductometric detection have also been coupled to flow systems, with notable advantages in terms of automation, precision, and sampling rate in comparison with the manual counterparts. 

See also Infrared Spectroscopy Overview. Mass Spectrometry Overview. Nuclear Magnetic Resonance Spectroscopy Overview. Raman Spectroscopy Surface-Enhanced. X-Ray Absorption and Diffraction Overview. 

Recent developments in the mechanisms of corrosion inhibition have been discussed in reviews dealing with acid solutions " and neutral solu-tions - . Novel and improved experimental techniques, e.g. surface enhanced Raman spectroscopy , infrared spectroscopy. Auger electron spectroscopyX-ray photoelectron spectroscopyand a.c. impedance analysis have been used to study the adsorption, interaction and reaction of inhibitors at metal surfaces. 

QCMB RAM SBR SEI SEM SERS SFL SHE SLI SNIFTIRS quartz crystal microbalance rechargeable alkaline manganese dioxide-zinc styrene-butadiene rubber solid electrolyte interphase scanning electron microscopy surface enhanced Raman spectroscopy sulfolane-based electrolyte standard hydrogen electrode starter-light-ignition subtractively normalized interfacial Fourier transform infrared... 

AC Impedance spectroscopy, 237 Auger electron spectroscopy, AES, 254 High resolution electron energy loss spectroscopy, HREELS, 43, 69 Infrared spectroscopy, IRS, 39, 69 Surface enhanced Raman spectroscopy, SERS, 256... 

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. 

Osawa, M Tsushima, M Mogami, H., Samjeske, G. and Yamakata, A. (2008) Structure of water at the electrified platinum-water interface a study by surface-enhanced infrared absorption spectroscopy. J. Phys. Chem. C, 112, 4248- 256. 

Yamakata, A., Uchida, T., Kubota, J. and Osawa, M. (2006) Laser-induced potential jump at the electrochemical interface probed by picosecond time-resolved surface-enhanced infrared absorption spectroscopy./. Phys. Chem. B, 110, 6423-6427. 

Figure 6.16 Attenuated total reflection surface enhanced infrared reflection absorption spectroscopy (ATR-SEIRAS) spectra for the oxidation of 0.1 M HCOOH in 0.5 M H2SO4 on a polycrystaUine electrode. The bands at 2055 -2075 and 1800-1850 cm are assigned to linear- and bridge-bonded CO, whereas the band at 1323 cm corresponds to adsorbed formate. (Reproduced from Samjeske et al. [2006].)...

Samjeske G, Miki A, Ye S, Osawa M. 2006. Mechanistic study of electrocatal3dic oxidation of formic acid at platinum in acidic solution by time-resolved surface-enhanced infrared absorption spectroscopy. J Phys Chem B 110 16559-16566. 

Watanabe M, Zhu Y, Uchida H. 2000. Oxidation of CO on a Pt-Fe alloy electrode studied by surface enhanced infrared reflection-absorption spectroscopy. J Phys Chem B 104 1762-1768. 

Sun SG, Cai WB, Wan LJ, Osawa M. 1999. Infrared absorption enhancement for CO adsorbed on Au films in perchloric acid solutions and effects of surface structure studied by cyclic voltammetry, scanning tunneling microscopy, and surface-enhanced IR spectroscopy. J Phys Chem B 103 2460-2466. 

Support effects in electiocatalysis, 567-586 Surface diffusion, 163, 173-177 Surface Enhanced Infrared Reflection Adsorption Spectroscopy (SEIRAS), 183... 

The sensitivity limitations of TLC-FT-Raman spectroscopy may be overcome by applying the SERS effect [782]. Unlike infrared, a major gain in Raman signal can be achieved by utilising surface activation and/or resonance effects. Surface-enhanced Raman (SER) spectra can be observed for compounds adsorbed on (rough) metahic surfaces, usually silver or gold colloids [783,784], while resonance Raman (RR) spectra... 

In recent years,3 4 however, there has been renewed interest in the study of the electrode/solution interface due in part to the development of new spectroscopic techniques such as surface-enhanced Raman spectroscopy,5-7 electrochemically modulated infrared reflectance spectroscopy and related techniques,8,9 second-harmonic generation,10-12 and others which give information about the identity and orientation of molecular species in the interfacial... 

The three most commonly applied external reflectance techniques can be considered in terms of the means employed to overcome the sensitivity problem. Both electrically modulated infrared spectroscopy (EMIRS) and in situ FTIR use potential modulation while polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) takes advantage of the surface selection rule to enhance surface sensitivity. 

Adsorption of 0.05 monolayers (ML) of CO on this surface gives rise to a peak at 2015 cm-1 corresponding to the internal C-0 stretch frequency of the molecule in the on-top adsorption site and one at 470 cm-1 due to the metal-molecule bond. The latter is not easily observable in infrared spectroscopy. Increasing the CO coverage to 0.33 ML enhances the intensity of the HREELS peaks. In addition, the C-O stretch frequency shifts upward because of dipole-dipole coupling [16, 17]. The LEED pattern corresponds to an ordered (V3xV3)R30° overlayer in Wood s notation (see the Appendix) in accordance with the coverage of 0.33 ML. 

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