IR spectroscopy measurement

Experimental methods of IR spectroscopy measurements can be divided into three main groups ... 

For some of the most intensively studied anions, increased information has not clarified the speciation or coordination of the adsorbed complex. For example, on the basis of IR data it has been claimed that sulphate adsorbs on goethite as both a bidentate and a monodentate surface complex (Parfitt and Smart, 1977 Persson and Lovgren, 1996). Some of the conflict may arise from differences in the conditions under which the experiments were carried out. Most IR spectroscopy measurements of adsorbed sulphate on Fe oxides were made on dried samples. Hug (1997) compared... 

X-ray powder diffraction was performed on a Phillips diffractometer using CuK radiation. IR spectroscopy measurements were carried out in a conventional greaseless cell. Wafers of 10 mg.cm 2 were pretreated under different conditions of temperature and vacuum the spectra in the 4000-1300 cm " region were recorded at room temperature. 

Phosphorus oxo-species adsorbed on alumina are present in a well-dispersed state up to a surface density of 2.9 x 10 P atom/pm (or 2.9 P atom/nm ) 31). IR spectroscopy measurements allowed identification of several types of hydroxyl groups on the y-alumina surface, such as type la (tetrahedral Al —OH, 3780 cm ), type lb (octahedral Al —OH, 3795 cm ), types 11a and Ilb (bridged OH between two Al atoms, 3736... 

The nature of the acidity was investigated in order to explain the catalytic activity of the calcined Co-substituted P-zeolite and the role played by the aluminic sites of this solid. A pyridine adsorption followed by IR spectroscopy measurements was performed on the calcined catalyst. It has been shown that adsorption of pyridine emphasized two distinct bands at 1548 cm and 1451 cm corresponding respectively to the adsorption on Brbnsted and Lewis sites [22], In the case of the calcined Co-substituted zeolite, only a weak band at 1548 cm appeared in the IR spectrum. Thus, we deduced that very few Bronsted sites were present in the catalyst. This could explain that the oxidation of cyclohexane into adipic acid in the presence of calcined Co-substituted aluminic P-zeolite was not inhibited. 

What does infrared (IR) spectroscopy measure, and what does it tell you about a compound ... 

IR spectroscopy, measuring the intensity and frequency shift of the absorption band of characteristic groups in the molecules (Lirova et al., 1972 Tager, 1972 Tager et al., 1975 Kuznet.sov et al., 1978). 

Authors express gratitude to Dr. V.S.Bezborodov for the synthesis of amines and T.L.Lebedeva for IR spectroscopy measurements and fruitfiil discussions. The research described in this publication was made possible in part by Grant No MR-300 from the International Science Foundation, Russian Foundation for Fundamental Research (Grant No 94-03-09535) and the Program "Universities of Russia". 

Ultrafast infrared (IR) spectroscopy measurements for 278 345 K suggest that the H-bond rearrangement in water is collective. According to MD simulations, breakage of the infinite H-bond network into a variety of H-bonded clusters can be expected for the temperature 573 K and density 700 kg Under these conditions the average number of H-bonds per... 

The effect of tenq)erature on the concentration of the opoi-chain form of D-finctose in D2O and water has been determined by FT-IR spectroscopy. Measurements by H-njru. spectroscopy of the temperature coefficients of chemical shifts, scalar coupling cxmstants, and exchange rates for hydroxyl protons in sucrose have provided no evidence for persistent hydrogen bonds in aqueous solution. ... 

Trombetta, M., Busca, G., Lenarda, M., Storaro, L., Ganzerla, R., Piovesan, L., Jimenez Lopez, A., Alcantara-Rodriguez, M., and Rodriguez-Castelldn, E. Solid acid catalysts from clays. Evaluation of surface acidity of mono- and bi-pillared smectites by FT-IR spectroscopy measurements, NH3-TPD and catalytic tests. Hpp/. Catal A Gen. 2000,193, 55-69. 

Specific chain conformation in the crystalline phase. These bands are used for the stmcture analysis of PCL on the PE substrate at 59 C. Here, attention is paid to the chain or chain segment orientation status of the PCL. To this end, polarized IR spectroscopy measurements were conducted during the annealing process of PCL melt on a PE substrate at 59 °C. 

The remaining sections in this chapter deal with two additional methods for the determination of the structures of organic compounds infrared (IR) spectroscopy and mass spectrometry (MS). IR spectroscopy is a very useful tool because it is capable of detecting the characteristic bonds of many functional groups through their absorption of infrared light. IR spectroscopy measures the vibrational excitation of atoms around the bonds that connect them. The positions of the absorption lines associated with this excitation depend on the types of functional groups present, and the IR spectrum as a whole displays a pattern unique for each individual substance. 

A qualitative study of the adsorption, in order to determine the functional group which takes part in the adsorption process, can be done by IR spectroscopy measurements. The OH stretching vibration of an hydroxylated siuface serves in prinicple as a spectroscopic probe of the molecular environment, and IR spectroscopy can be used to determine the chemical functionality and the donor acceptor properties of an oxide siuface upon adsorption of various probe molecules. Noller and Kladnig [22] found that the changes in the OH valence frequency values (Av values), upon adsorption of a variety of organic donor molecules on to acidic silica, were linearly related to the donor number of the adsorbate. 

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