Diffuse spectroscopy

Oil and 0)2, and (b) 2D shift-correlation spectra, involving either coherent transfer of magnetization [e.g., COSY (Aue et al, 1976), hetero-COSY (Maudsley and Ernst, 1977), relayed COSY (Eich et al, 1982), TOCSY (Braunschweiler and Ernst, 1983), 2D multiple-quantum spectra (Braun-schweiler et al, 1983), etc.] or incoherent transfer of magnedzation (Kumar et al, 1980 Machura and Ernst, 1980 Bothner-By et al, 1984) [e.g., 2D crossrelaxation experiments, such as NOESY, ROESY, 2D chemical-exchange spectroscopy (EXSY) (Jeener et al, 1979 Meier and Ernst, 1979), and 2D spin-diffusion spectroscopy (Caravatti et al, 1985) ]. 

Cameron, K. S. Fielding, L. NMR Diffusion Spectroscopy as a Measure of Host-Guest Complex Association Constants and as a Probe of Complex Size. J. Org. Chem. 2001, 66, 6891-6895. 

At the beginning, the electric double layer at the solid-aqueous electrolyte solution interface was characterized by the measurements of the electrokinetic potential and stability of dispersed systems. Later, the investigations were supported by potentiometric titration of the suspension, adsorption and calorimetric measurements [2]. Now, much valuable information on the mechanism of the ion adsorption can be obtained by advanced spectroscopic methods (especially infrared ATR and diffuse spectroscopy) [3], Mosbauer spectroscopy [4] and X-ray spectroscopy [5]. Some data concerning the interface potential were obtained with MOSFET [6], and AFM [7]. An enthalpy of the reaction of the metal oxide-solution systems can be obtained by... 

Macchioni A, Ciancaleoni G, Zuccaccia C, Zuccaccia D (2008) Determining accurate molecular sizes in solution through NMR diffusion spectroscopy. Chem Soc Rev 37 479 -89... 

Pulsed Field Gradient—Spin Echo (PGSE) Diffusion Spectroscopy... 

Figure 27 Pulse sequence for stimulated echo PGSE diffusion spectroscopy...

Fig. 4.1. (a) General scheme for spin-diffusion spectroscopy and (b) a possible realization in the context of two-dimensional spectroscopy. 

Chambers, J., Van Wyk, C.B., Baker, C.W., and Barnes, R J. 1992b. NIR analysis for the detection of insect pests in cereal grains. In Proceedings of the International Diffuse Spectroscopy Conferences, August 1992 (R.A. Taylor, ed.), pp. 96-100. The Council of Near Infrared Spectroscopy, Gaithersburg, MD. 

We have so far been concerned with 2D spin-diffusion spectroscopy. There are, however, two ID experiments that are likely to be applied to catalytic problems selective excitation 72,85,861 and rotational resonance (87-93]. Selective excitation of selected resonances using the DANTE pulse trains [94] can be used to measure specific C - C connectivity in complex, multiple C-labeled solids (86). Rotational resonance can be achieved by adjusting the MAS rate to an integer fraction of the chemical shift difference between two selected carbon resonances n being a small integer. 

Cameron KS, Fielding L. NMR diffusion spectroscopy as a measure of host—guest complex association constants and as a probe of complex size. J Org Chem 2001 66 6891-5. 

T. Isaksson, Z. Wang, B. Kowalski. Optimised scaling (OS-2) regression apphed to near infrared diffuse spectroscopy data from food products. J Near Infrared Spectrosc 1 85-97, 1993. 

T. Isaksson, G. Tdgersen, A. Iversen, K. I. HUdrum. Nondestructive determination of fat, moisture and protein in sahnon filets by use of near infrared diffuse spectroscopy. J Sci FoodAgric 69 95-100,1995. 

J. P. Wold, T. Isaksson. Non-destructive determination of fat and moisture in whole Atlantic salmon by near-infrared diffuse spectroscopy. J FoodSci 62 734-736, 1997. 

The attachment of pyrene or another fluorescent marker to a phospholipid or its addition to an insoluble monolayer facilitates their study via fluorescence spectroscopy [163]. Pyrene is often chosen due to its high quantum yield and spectroscopic sensitivity to the polarity of the local environment. In addition, one of several amphiphilic quenching molecules allows measurement of the pyrene lateral diffusion in the mono-layer via the change in the fluorescence decay due to the bimolecular quenching reaction [164,165]. 

Foam rheology has been a challenging area of research of interest for the yield behavior and stick-slip flow behavior (see the review by Kraynik [229]). Recent studies by Durian and co-workers combine simulations [230] and a dynamic light scattering technique suited to turbid systems [231], diffusing wave spectroscopy (DWS), to characterize coarsening and shear-induced rearrangements in foams. The dynamics follow stick-slip behavior similar to that found in earthquake faults and friction (see Section XU-2D). 

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]. 

Morris K F and Johnson C S Jr 1993 Resolution of discrete and continuous molecular size distributions by means of diffusion-ordered 2D NMR spectroscopy J. Am. Chem. See. 115 4291-9... 

Vreugdenhil A J and Butler I S 1998 Investigation of MMT adsorption on soils by diffuse reflectance infrared spectroscopy DRIFTS and headspace analysis gas-phase infrared spectroscopy HAGIS Appl. Organomet. Chem. 

Cross A J, Waldeck D H and Fleming G R 1983 Time resolved polarization spectroscopy level kinetics and rotational diffusion J. Chem. Phys. 78 6455-67... 

Ambrose W P and Moerner W E 1991 Fluorescence spectroscopy and spectral diffusion of single impurity molecules in a crystal Nature 349 225-7... 

Tittel J, Kettner R, Basche T, Brauchle C, Quante FI and Mullen K 1995 Spectral diffusion in an amorphous polymer probed by single molecule spectroscopy J. Lumin. 64 1-11... 

Diffuse reflectance infrared Fourier transform spectroscopy... 

Several properties of the filler are important to the compounder (279). Properties that are frequentiy reported by fumed sihca manufacturers include the acidity of the filler, nitrogen adsorption, oil absorption, and particle size distribution (280,281). The adsorption techniques provide a measure of the surface area of the filler, whereas oil absorption is an indication of the stmcture of the filler (282). Measurement of the sdanol concentration is critical, and some techniques that are commonly used in the industry to estimate this parameter are the methyl red absorption and methanol wettabihty (273,274,277) tests. Other techniques include various spectroscopies, such as diffuse reflectance infrared spectroscopy (drift), inverse gas chromatography (igc), photoacoustic ir, nmr, Raman, and surface forces apparatus (277,283—290). 

Photon Correlation Spectroscopy. Photon correlation spectroscopy (pcs), also commonly referred to as quasi-elastic light scattering (qels) or dynamic light scattering (dls), is a technique in which the size of submicrometer particles dispersed in a Hquid medium is deduced from the random movement caused by Brownian diffusion motion. This technique has been used for a wide variety of materials (60—62). 

Combustion chemistry in diffusion flames is not as simple as is assumed in most theoretical models. Evidence obtained by adsorption and emission spectroscopy (37) and by sampling (38) shows that hydrocarbon fuels undergo appreciable pyrolysis in the fuel jet before oxidation occurs. Eurther evidence for the existence of pyrolysis is provided by sampling of diffusion flames (39). In general, the preflame pyrolysis reactions may not be very important in terms of the gross features of the flame, particularly flame height, but they may account for the formation of carbon while the presence of OH radicals may provide a path for NO formation, particularly on the oxidant side of the flame (39). 

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