Raman reflection spectroscopy

Resonance Raman reflection spectroscopy of monolayers is possible, as illustrated in Fig. IV-14 for cetyl orange [157]. The polarized spectra obtained with an Ar ion laser allowed estimates of orientational changes in the cetyl orange molecules with a. 

Vibrational Spectroscopy. Infrared absorption spectra may be obtained using convention IR or FTIR instrumentation the catalyst may be present as a compressed disk, allowing transmission spectroscopy. If the surface area is high, there can be enough chemisorbed species for their spectra to be recorded. This approach is widely used to follow actual catalyzed reactions see, for example. Refs. 26 (metal oxide catalysts) and 27 (zeolitic catalysts). Diffuse reflectance infrared reflection spectroscopy (DRIFT S) may be used on films [e.g.. Ref. 28—Si02 films on Mo(llO)]. Laser Raman spectroscopy (e.g.. Refs. 29, 30) and infrared emission spectroscopy may give greater detail [31]. 

Some of the transition metal macrocycles adsorbed on electrode surfaces are of special Interest because of their high catalytic activity for dloxygen reduction. The Interaction of the adsorbed macrocycles with the substrate and their orientation are of Importance In understanding the factors controlling their catalytic activity. In situ spectroscopic techniques which have been used to examine these electrocatalytlc layers Include visible reflectance spectroscopy surface enhanced and resonant Raman and Mossbauer effect spectroscopy. This paper Is focused principally on the cobalt and Iron phthalocyanlnes on silver and carbon electrode substrates. 

Of special Interest as O2 reduction electrocatalysts are the transition metal macrocycles In the form of layers adsorptlvely attached, chemically bonded or simply physically deposited on an electrode substrate Some of these complexes catalyze the 4-electron reduction of O2 to H2O or 0H while others catalyze principally the 2-electron reduction to the peroxide and/or the peroxide elimination reactions. Various situ spectroscopic techniques have been used to examine the state of these transition metal macrocycle layers on carbon, graphite and metal substrates under various electrochemical conditions. These techniques have Included (a) visible reflectance spectroscopy (b) laser Raman spectroscopy, utilizing surface enhanced Raman scattering and resonant Raman and (c) Mossbauer spectroscopy. This paper will focus on principally the cobalt and Iron phthalocyanlnes and porphyrins. 

Time-domain Raman measurement of molecular submonolayers by time-resolved reflection spectroscopy. /. Phys. Chem. B, 108, 1525-1528. 

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... 

IR spectra, 27 283, 284 magnetic measurements, 27 280 oxidized state, 27 289 Raman spectra, 27 284 reduced state, 27 291 reflectance spectroscopy, 27 279 X-ray diffraction, 27 272, 273 support interactions, 27 290 Cobalt monoxide, field effect, 27 44, 45 Cobalt(nickel)-molybdenum-sulfide catalysts, 42 417... 

The electrochemistry and cristallography of the nickel oxides have been extensively investigated in connection with the improvement of storage batteries . In-situ UV/visible reflectance spectroscopy and laser raman spectroscopy of the... 

Metal oxides have surface sites which are acidic, basic, or both and these characteristics control important properties such as lubrication, adhesion, and corrosion. Some of the newer infrared techniques such as lazer-Raman and Fourier transform infrared reflection spectroscopy are important tools for assessing just how organic acids and bases interact with the oxide films on metal surfaces. Illustrations are given for the adsorption of acidic organic species onto aluminum or iron surfaces, using Fourier transform infrared reflection spectroscopy. 

An analogous ship-in-bottle complex, [VO(bpy)2]2+-NaY, could be designed starting from a vanadyl exchanged Y zeolite upon bpy addition.[97] Strong spectroscopic proof for the formation of such complex was evident from FT-Raman, FTIR, diffuse reflectance spectroscopy, XPS and EPR as follows ... 

Table 3.4 summarizes the phonon-mode frequencies of ZnO bulk samples and ZnO thin films, as obtained by Raman scattering spectroscopy, IR-reflection measurements, and IRSE. 

FIGURE 1 Phonon, plasmon and phonon-plasmon coupled modes in Raman and infrared reflection spectroscopy as a function of free electron density (+ data from [25], see also [3]) [24],... 

A. Seas and C. Christofides, Transmission and Reflection Spectroscopy on Ion Implanted Semiconductors A. Othonos and C. Christofides, Photoluminescence and Raman Scattering of Ion Implanted Semiconductors. Influence of Annealing... 

SnOz nanocrystals with a particle size ranging from 3.5 to 17.9 nm are prepared by heating a smaller SnOz nanocrystal at different temperatures. The samples are characterized by powder X-ray diffraction, Raman spectroscopy and UV-vis diffuse reflectance spectroscopy. The Raman spectra show a surface-related vibration mode, which is dependent on the crystallite size of the SnOz nanocrystals. The quantum confinement effect is observed. The UV-vis diffuse reflectance spectroscopic results indicate that the band gap of the SnOz nanocrystals increases from 3.65 eV to 3.95 eV when the particle size decreases from 4.0 nm to 3.6 nm. 

A novel method has been developed for controlling the particle size of inorganic nanocrystalls. For example, a monodispersed nanocrystalline YSZ with an average particle size of 4.7 nm is obtained by using this method [10]. A very high surface area of 165 m /g and a significant band gap increase from 4.13 to 5.44 eV are observed. Smaller SnOz nanocrystals are also prepared by this method [11]. Here we report the Raman spectra and UV-vis diffuse reflectance spectroscopy (DRS) results of the SnOz nanocrystals with different particle sizes. 

These coefficients have the dimension of reciprocal length (Mills, 1988), in this context, cm Kubelka and Munk (1931) described the optical properties of pigments by employing the parameters a and r. The Kubelka-Munk theory is the basis of diffuse reflection spectroscopy (Sec. 6.4). We have extended the Kubelka-Munk approach in order to describe the Raman scattering of crystal powders (Schrader and Bergmann, 1967). The results can also be applied to liquids and transparent solids. The procedure is as follows ... 

Ferraro JR, Nakamoto K (1994) Introductory Raman Spectroscopy, Academic Press, New York Ferraro JR, Rein AJ (198.5) Applications of Diffuse Reflectance Spectroscopy in the Far-Infrared Region. In Ferraro JR, Basile LJ (eds) Fourier Transform Infrared Spectroscopy, vol 4. Academic, Orlando... 

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