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Attenuated Total Reflection ATR

The evanescent field is a non-transverse wave along the optical surface, whose ampHtude can be expressed as an exponential function along the z-axis into the rare medium  [Pg.75]

If medium 1 is absorbing, the evanescent field wiU be absorbed and less intensity can be reflected (attenuated total reflection (ATR)). An ATR spectrum is similar to the conventional absorption spectrum except for the band intensities at longer wavelengths. At longer wavelengths the evanescent field penetrates ever deeper into the sample, equivalent to an increasing sample thickness. Sometimes an empirical so-called ATR correction is appHed in order to compensate across the spectrum for the linear wavelength increase in Eq. (10)  [Pg.76]

Other differences may occur due to surface effects between the sample and the optical crystal or due to absorption changes across the sample. Single-reflection or multi-reflection crystals may be used. The measured reflectivity depends on the number of reflections as well as on the efficiency of contact between sample and substrate surface. [Pg.76]

An important advantage of the ATR technique is its applicability to turbid solutions, aqueous solutions included. Suspended particles are surrounded by a thin Hquid film (hydrating shell). This shell forms also the phase boundary to the ATR crystal surface so that the evanescent field will not scattered by the particle. [Pg.76]


Figure Bl.22.4. Differential IR absorption spectra from a metal-oxide silicon field-effect transistor (MOSFET) as a fiinction of gate voltage (or inversion layer density, n, which is the parameter reported in the figure). Clear peaks are seen in these spectra for the 0-1, 0-2 and 0-3 inter-electric-field subband transitions that develop for charge carriers when confined to a narrow (<100 A) region near the oxide-semiconductor interface. The inset shows a schematic representation of the attenuated total reflection (ATR) arrangement used in these experiments. These data provide an example of the use of ATR IR spectroscopy for the probing of electronic states in semiconductor surfaces [44]-... Figure Bl.22.4. Differential IR absorption spectra from a metal-oxide silicon field-effect transistor (MOSFET) as a fiinction of gate voltage (or inversion layer density, n, which is the parameter reported in the figure). Clear peaks are seen in these spectra for the 0-1, 0-2 and 0-3 inter-electric-field subband transitions that develop for charge carriers when confined to a narrow (<100 A) region near the oxide-semiconductor interface. The inset shows a schematic representation of the attenuated total reflection (ATR) arrangement used in these experiments. These data provide an example of the use of ATR IR spectroscopy for the probing of electronic states in semiconductor surfaces [44]-...
Attenuated total reflectance (ATR) cell for use In Infrared spectroscopy. [Pg.393]

The attenuated total reflectance (ATR) technique is used commonly in the near-infrared for obtaining absorption spectra of thin Aims and opaque materials. The sample, of refractive index i, is placed in direct contact with a material which is transparent in the region of interest, such as thallium bromide/thallium iodide (known as KRS-5), silver chloride or germanium, of relatively high refractive index so that Then, as Figure 3.f8... [Pg.64]

Attenuated total reflection (ATR), also called internal reflection, is based on the phenomenon of total internal reflection. In ATR the infrared beam is directed into an infrared-transmitting crystal so that it strikes the crystal surface at less than the critical angle and undergoes total internal reflection. [Pg.199]

Surface analysis has made enormous contributions to the field of adhesion science. It enabled investigators to probe fundamental aspects of adhesion such as the composition of anodic oxides on metals, the surface composition of polymers that have been pretreated by etching, the nature of reactions occurring at the interface between a primer and a substrate or between a primer and an adhesive, and the orientation of molecules adsorbed onto substrates. Surface analysis has also enabled adhesion scientists to determine the mechanisms responsible for failure of adhesive bonds, especially after exposure to aggressive environments. The objective of this chapter is to review the principals of surface analysis techniques including attenuated total reflection (ATR) and reflection-absorption (RAIR) infrared spectroscopy. X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and secondary ion mass spectrometry (SIMS) and to present examples of the application of each technique to important problems in adhesion science. [Pg.243]

In order to characterize the surface regions of a sample that has been modified in some way, as is usually the case in adhesion-related investigations, some sort of a reflection experiment is required. Two types of experiments, attenuated total reflection (ATR) and reflection-absorption infrared spectroscopy (RAIR),... [Pg.244]

Surface composition and morphology of copolymeric systems and blends are usually studied by contact angle (wettability) and surface tension measurements and more recently by x-ray photoelectron spectroscopy (XPS or ESCA). Other techniques that are also used include surface sensitive FT-IR (e.g., Attenuated Total Reflectance, ATR, and Diffuse Reflectance, DR) and EDAX. Due to the nature of each of these techniques, they provide information on varying surface thicknesses, ranging from 5 to 50 A (contact angle and ESCA) to 20,000-30,000 A (ATR-IR and EDAX). Therefore, they can be used together to complement each other in studying the depth profiles of polymer surfaces. [Pg.69]

A number of techniques have been employed that are capable of giving information about amorphous phases. These include infrared spectroscopy, especially the use of the attenuated total reflection (ATR) or Fourier transform (FT) techniques. They also include electron probe microanalysis, scanning electron microscopy, and nuclear magnetic resonance (NMR) spectroscopy. Nor are wet chemical methods to be neglected for they, too, form part of the armoury of methods that have been used to elucidate the chemistry and microstructure of these materials. [Pg.359]

The experimental apparatus consists of a gas flow system with a four-port valve, a multi-reflection Attenuated Total Reflection (ATR) accessory (Pike Technologies), and a custom reactor manifold mounted to the ATR top plate, shown in Fig. 45.1. The ATR reactor manifold consists of (i) a Cap2 window for UV irradiation, (ii) an inlet and outlet port, and (iii) an injection port for the liquid phase reactant. [Pg.406]

The photocatalytic oxidation of alcohols constitutes a novel approach for the synthesis of aldehydes and acid from alcohols. Modification of Ti02 catalyst with Pt and Nafion could block the catalyst active sites for the oxidation of ethanol to CO2. Incorporation of Pt resulted in enhanced selectivity towards formate (HCOO ad)-Blocking of active sites by Nafion resulted in formation of significantly smaller amounts of intermediate species, CO2 and H2O, and accumulation of photogenerated electrons. The IR experimental teclmique has been extended to Attenuated Total Reflectance (ATR), enabling the study of liquid phase photocatalytic systems. [Pg.471]

Fixed pathlength transmission flow-cells for aqueous solution analysis are easily clogged. Attenuated total reflectance (ATR) provides an alternative method for aqueous solution analysis that avoids this problem. Sabo et al. [493] have reported the first application of an ATR flow-cell for both NPLC and RPLC-FUR. In micro-ATR-IR spectroscopy coupled to HPLC, the trapped effluent of the HPLC separation is added dropwise to the ATR crystal, where the chromatographic solvent is evaporated and the sample is enriched relative to the solution [494], Detection limits are not optimal. The ATR flow-cell is clearly inferior to other interfaces. [Pg.491]

For solid-phase samples or for membrane interaction studies, it can be very useful to use the alternative sampling technique of attenuated total reflectance (ATR). Films or solutions can be placed on a specially... [Pg.145]

In materials investigations surface-sensitive techniques are of special interest. The major contribution of infrared spectroscopy to this field is internal reflection spectroscopy (IRS), often called the "attenuated total reflection" (ATR) technique. To describe theory and principle, electromagnetic wave theory must be apphed [33]. [Pg.535]

FTIR spectroscopy was conducted on the white residue using an attenuated total reflection (ATR) attachment [l].1 After the blister was opened, the ATR... [Pg.612]

Internal reflectance (attenuated total reflectance ATR ). The internal reflectance or, more usually, attenuated total reflectance (ATR), technique depends on the total reflectance of an IR beam at the internal face of an IR-transparent crystal of high IR refractive index, as shown in Figure 2.38. Medium 1 is a prism of such a material (for example, Si, Ge or KRS-5 [thallous bromide- iodide]), medium 2 is a thin coating of a metal (Au, Pt, Fe) which forms the working electrode and medium 3 is the electrolyte. The... [Pg.96]

For IR sensing, three transducer principles are standard classical transmission for (sufficiently) transparent samples, (diffuse) reflection for opaque samples, in particular solids and strongly turbid liquids and attenuated total reflection (ATR), in particular for strongly absorbing samples and fluids with varying amounts of suspended solids or gas bubbles. [Pg.129]

ATR spectroscopy devices, 24 114. See also Attenuated total reflection (ATR) Attachment materials... [Pg.78]


See other pages where Attenuated Total Reflection ATR is mentioned: [Pg.393]    [Pg.314]    [Pg.423]    [Pg.253]    [Pg.244]    [Pg.353]    [Pg.10]    [Pg.497]    [Pg.95]    [Pg.187]    [Pg.414]    [Pg.539]    [Pg.463]    [Pg.317]    [Pg.309]    [Pg.409]    [Pg.677]    [Pg.740]    [Pg.741]    [Pg.132]    [Pg.318]    [Pg.69]    [Pg.392]    [Pg.266]    [Pg.266]    [Pg.78]    [Pg.78]   


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ATR

ATR-FTIR (attenuated total reflectance-Fourier transform

ATTENUATED TOTAL

Atred

Attenuated Total Infrared Internal Reflectance (ATR) Spectroscopy (Spectra-Tech)

Attenuated Total Reflection (ATR) Mode

Attenuated Total Reflection (ATR) Technique

Attenuated Total Reflection Infrared Spectrometry (ATR)

Attenuated total internal reflection (ATR

Attenuated total reflectance

Attenuated total reflectance (ATR

Attenuated total reflectance (ATR

Attenuated total reflectance Attenuation

Attenuated total reflection spectroscopy (ATR

Attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR

Attenuation total reflection

Attenuator attenuated total reflection

Reflection, attenuated total

Reflectivity total

Total reflection

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