Fourier transform infrared reflection

Recent work in our laboratory has shown that Fourier Transform Infrared Reflection Absorption Spectroscopy (FT-IRRAS) can be used routinely to measure vibrational spectra of a monolayer on a low area metal surface. To achieve sensitivity and resolution, a pseudo-double beam, polarization modulation technique was integrated into the FT-IR experiment. We have shown applicability of FT-IRRAS to spectral measurements of surface adsorbates in the presence of a surrounding infrared absorbing gas or liquid as well as measurements in the UHV. We now show progress toward situ measurement of thermal and hydration induced conformational changes of adsorbate structure. The design of the cell and some preliminary measurements will be discussed. 

Reaction products can also be identified by in situ infrared reflectance spectroscopy (Fourier transform infrared reflectance spectroscopy, FTIRS) used as single potential alteration infrared reflectance spectroscopy (SPAIRS). This method is suitable not only for obtaining information on adsorbed products (see below), but also for observing infrared (IR) absorption bands due to the products immediately after their formation in the vicinity of the electrode surface. It is thus easy to follow the production of CO2 versus the oxidation potential and to compare the behavior of different electrocatalysts. 

It is only since 1980 that in situ spectroscopic techniques have been developed to obtain identification of the adsorbed intermediates and hence of reliable reaction mechanisms. These new infrared spectroscopic in situ techniques, such as electrochemically modulated infrared reflectance spectroscopy (EMIRS), which uses a dispersive spectrometer, Fourier transform infrared reflectance spectroscopy, or a subtractively normalized interfacial Fourier transform infrared reflectance spectroscopy (SNIFTIRS), have provided definitive proof for the presence of strongly adsorbed species (mainly adsorbed carbon monoxide) acting as catalytic poisons. " " Even though this chapter is not devoted to the description of in situ infrared techniques, it is useful to briefly note the advantages and limitations of such spectroscopic methods. 

B.B. Perston, M.L. Hamilton, B.E. Williamson, PW. Harland, M.A. Thomson and P.J. Melling, Grazing-angle fiber-optic Fourier transform infrared reflection-absorption spectroscopy for in situ detection and quantification of two active pharmaceutical ingredients on glass. Anal. Chem., 79, 1231-1236 (2007). 

PVI-1 and UDI have been Investigated as emtl-oxldatlon agents for Cu in dry air at elevated temperatures [ -30]. Fourier transform Infrared reflection-absorption spectroscopy TFT-IR RAS) was... 

Fourier transform infrared reflection-absorption spectroscopy (FT-IFRAS) is applied to the study of corrosion protection of copper by an organic coating. Poly-N-vinyliroidazole (PVI(D) and poly-4(5)-vinylimidazole (PVI(4)) are demonstrated to be effective new polymeric anti-corrosion agents for copper at elevated temperatures. Oxidation of copper is suppressed even at 400° C. PVI(1) and PVI(4) are more effective anti-oxidants than the most commonly used corrosion inhibitors, benzotriazole and undecyllmldazole, at elevated temperatures. These new polymeric agents are water soluble and easy to treat the metal surface. 

Fourier transform infrared reflection-absorption spectroscopy studies (FTIR-RAS) by Tolbert and coworkers (Zondlo et al., 1998) of the uptake of HNO, on ice at 185 K have shown that a supercooled liquid forms on the surface upon evaporation of water, the ice film becomes more concentrated in HN03 and at stoichiometries of 3 1 and 2 1 H20 HN03, respectively, NAT and NAD crystallize out. The reactions of C10N02 and N2Os with the ice also led to the formation of supercooled H20-HN03 liquid layers on the ice surface. 

The ILs interact with surfaces and electrodes [23-25], and many more studies have been done that what we can cite. As one example, in situ Fourier-transform infrared reflection absorption spectroscopy (FT-IRAS) has been utilized to study the molecular structure of the electrified interphase between a l-ethyl-3-methylimidazolium tetrafluoroborate [C2Qlm][BF4] liquid and gold substrates [26]. Similar results have been obtained by surface-enhanced Raman scattering (SERS) for [C4Cilm][PFg] adsorbed on silver [24,27] and quartz [28]. 

Figure 9.12 Spectroelectrochemical cell for Fourier-transform infrared reflection absorption spectroscopy (FTIRRAS). (A) Cell components showing Teflon bar for controlling the sample path length (B) retroreflection absorption optics for use with this cell. [From I.T. Bae, X. Xing, E.B. Yeager, and D. Scherson, Anal. Chem. 61 1164 (1989). Copyright 1989 American Chemical Society.]...

Organic Monolayer Studies Using Fourier Transform Infrared Reflection Spectroscopy... 

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. 

Golden WG (1985) Fourier Transform Infrared Reflection-Absorption Spectroscopy. In Ferraro J R, Basile LJ (eds) Fourier Transform Infrared Spectroscopy, Applications to Chemical Systems, vol 4, Academic, Orlando, pp 315 - 344 Golden WG, Dunn DS, Overend J (1981) J Catalysis 71 395 Goldman A, Saunders RS (1979) J Quant Spectrosc Rad Transfer 21 155... 

FTIR-ATR Fourier transform infrared reflection-attenuated total reflection... 

F. Caruso, D.N. Furlong, K. Ariga, I. Ichinose, T. Kimitake, Characterization of Polyelectrolyte-Protein Multilayer Films by Atomic Force Microscopy, Scanning Electron Microscopy, and Fourier Transform Infrared Reflection-Absorption Spectroscopy , Langmuir, 14,4559 (1998)... 

Later on, due to the development of Fourier Transform Infrared Reflectance Spectroscopy (FTIRS) this last technique was adapted to the in situ observation of adsorbed species and reaction products at the electrode-electrolyte interface. Some important details of these techniques are described below. 

In situ IR spectra were recorded using, either the Single Potential Alteration Iirfrared Reflectance Spectroscopy (SPAIRS), also called Linear Potential Sweep-Fourier Transform Infrared Reflectance Spectroscopy (LPS-FTIRS), or the Subtractively Normalized Interfacial Fourier Transform Infrared Reflectance Spectroscopy (SNIFTIRS). ... 

It has been suggested that the first step of reaction (6) may be the formation of a carboxylic species COOHads. Carboxyl radicals have indeed been observed by Zhu et al." for potentials lower than 0.65 V using Fourier Transform infrared Reflectance Absorption Spectroscopy with the Attenuated Total Reflection mode (ATR-FTtR). Moreover Anderson et al." made numerical simulation which indicated that the formation of an adsorbed carboxylic species was energetically more favorable. Here, it has to be noted that the electro-oxidation of CO being a stracture sensitive reaction (sensitive to the superficial stracture symmehy" and to the presence of surface defects) this species can be used to study the activity of a catalyst but also as a molecular probe to characterize the catalytic surface. ... 

Besides (CO)ads, some other adsorbed species, such as (-CHO)ads or (-COOH)ads, were identified, on a platinum electrode, by infrared reflectance spectroscopy, i.e., EMIRS" (Fig. 11) and Fourier transform infrared reflectance spectroscopy. ... 

Golden WG. (1985) Fourier Transform Infrared Reflection-Absorption Spectroscopy. Academic Press, Orlando. 

FT-IRRAS Fourier transform infrared reflection-absorption sepctroscopy... 

Fourier transform infrared reflectance spectrum (FTIR) results indicate that AChE was immobilized successfully on the MWCNT/PDDA surface. CV results show that electrooxidation of thiocholine occurs at a much lower oxidation potential +0.55 V at MWCNT/GCE and the electrooxidation current is ten times higher than that of bare GCE. In addition, amperometric results show that the response of thiocholine at MWCNT/GCE was 200 times more than that of bare GCE. This significant enhancement in the anodic oxidation current of the enzymatic product thiocholine can be attributed to the fast electron transfer and... 

Barner B J, Green M J, Saez E I and Corn R M 1991 Polarization modulation Fourier transform infrared reflectance measurements of thin films and monolayers at metal surfaces utilizing real-time sampling electronics Anal. Chem. 63 55-60... 

Hoffmann F M and Weisel M D 1993 Fourier transform infrared reflection absorption spectroscopy studies of... 

SW-EURS Square wave Fourier transform infrared reflection spectroscopy... 

X. Bin, Electrochemical and polarization modulation Fourier transform infrared reflection absorption spectroscopic studies of phospholipids bilayers on a Au(lll) electrode surface . PhD thesis, University of Guelph, 2005. 

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