Infrared spectroscopic measurements

Recently, time-resolved infrared spectroscopic measurements revealed evidence for the first direct observation of an acyl nitroso compound in solution [22]. Pho-... 

Tautomerism both in the solid state and in solution is confirmed by infrared spectroscopic measurements on all three compounds [54,55]. The highest content of ketohydrazone form within the three isomeric phenylazonaphthols occurs, in solution, with 2-phenylazo-l-naphthol [56]. A 15N-n.m.r. study of some azo dyes derived from H acid and related intermediates has confirmed the dominance of the ketohydrazone tautomer [57]. Similar findings have been obtained using high-field H- and 13C-n.m.r. spectroscopy [58]. 

Infrared spectroscopic measurements of the gas travelling between steps 1 and 2 of the unit show that the HOCl is absorbed completely in step two. However, the chlorine dioxide that is formed in step one is hardly absorbed at all in step two with most being stripped from the gas owing to its low solubility and high flow rate. 

I would also like to thank Dr. D. A. Dyk and Dr. S. L. Gupta for their skillful assistance for my experiments and us id discussions. Specific thanks go to Dr. I. Bae for his instruction for the in situ infrared spectroscopic measurement. I am thankful for Dr. S. Wasmus for the assistance in the use of the on-line mass spectrometer. I thank Dr. K. Sashikata for the instruction for the platinum single crystal studies. 

Infrared spectroscopic measurements were carried ou" in a conventional greaseless IR cell. Wafers of 10 mg.cm were pretreated overnight at 400 °C and J.33 x 10 Pa of dynamic vacuum. 

Thio-l,2,3,4-thiatriazole was originally thought to have an open structure, azidodithiocarbonic acid, but Lieber et al. concluded from infrared spectroscopic measurements that it aetually possesses the closed 1,2,3,4-thiatriazole structure <57JOC1750>. 

Infrared spectroscopic measurement was performed by Jasco FT-IR 230S using an in-situ cell. Hydrogen sulfide adsorption was carried out by introducing 40 Torr of hydrogen sulfide into the cell at 200°C, followed by evacuation at the same temperature for 0.5 hour. Pyridine adsorption was performed by introducing 10 Torr of pyridine vapour into the cell at 150°C, followed by evacuation at the same temperature for 0.5 hour. 

The opposed anvil cell consists of two optical anvils and a gasket, located between the parallel faces of the two opposing anvils. Samples are placed in the hole of the gasket and are pressurized when the opposed anvils are pushed towards each other. The most common material for anvils is diamond. For mid and far infrared spectra, type Ila diamonds are used, while low-fluorescent type la diamonds are used for Raman spectroscopic measurements [5]. We have also devised a glass anvil cell for Raman spectroscopic measurements [6], and a calcium fluoride anvil cell for infrared spectroscopic measurements [7] with attainable working pressures of 13 and 6 kbar, respectively. Diagrams, for the interested reader, of the window and opposed anvil cells can be found in reference 1. 

The situation, however, is different for the infrared spectroscopic measurements with opposed anvil cells. The source beam in commercial Fourier transform infrared spectrometers is generally focused to about 1 cm diameter at the sample, whereas the diameter of the gasket hole in the high pressure cell is only about 0.3 mm. Therefore, a source beam condensing system is required in order to obtain infrared spectra with a good signal-to noise ratio. Commercial beam condensers (4X, 6X) could, in principle, be adapted for these purposes. In practice, however, the mirrors of the... 

The components of the silanol number (free and bridged hydroxyls) were determined by the deuterium exchange method and infrared spectroscopic measurements.36... 

A //ads, are negative, and it is convenient to define the heat of adsorption as being equal to -A//adS. Figure 3 shows initial heats for hydrogen and isobutylene adsorptions of 95 and 125 kJ/mol, respectively. In both cases, the heats of adsorption decrease with increasing coverage. The observed heat of isobutylene adsorption has been attributed to the formation of either di-er-bonded or r-bonded olefin on the tin-modified platinum surface (46). Recent microcalorimetric and infrared spectroscopic measurements characterizing adsorption of ethylene indicate that the addition of tin to... 

If the a hydrogen is substituted as, for example, in a-amino isobutyric acid (Aib), then the conformational energy (< >,t j) map is very restricted, and the preferred form of Aib peptides is computed to be the 310 rather than the a-helical form.150 This prediction has been verified by NMR and infrared spectroscopic measurements on solutions of oligomers of Aib.151 The stability of the 310-helix for short poly(Aib-L-alanine) polypeptides and the increased stabilization of the a-helical form with a lengthening of the chain have been demonstrated recently.152... 

The surface chemistry of zinc oxide is of particular interest in relation to its catalytic and photocatalytic properties. For example the (0001) hexagonal crystal plane appears to have a special role in the catalytic methanol-synthesis reaction (Bowker et al., 1983). The chemisorption of CO and dissociative chemisorption of H2 occur on the exposed Zn2+ cations Bolis et al. (1986) have found that the relative magnitude of this active area of ZnO was highly dependent on the nature of the precursor (oxalate, carbonate of Zn). Similar conclusions can be drawn from the infrared spectroscopic measurements of Chauvin et al. (1986). 

A methyl radical flux of j 2 x 1015 cm 2s 1 is directed to the surface of a pre-deposited a-C D film. For film deposition, CD4 was used as the plasma source gas instead of CH4. Isotopic labelling of the substrate film is very advantageous for in-situ infrared spectroscopic measurements since it... 

Dixon J. E., Stolper E., and Delaney J. R. (1988) Infrared spectroscopic measurements of CO2 and H2O in Juan de Fuca Ridge basaltic glasses. Earth Planet. Sci. Lett. 90, 87-104. 

The electrochemical and infrared spectroscopic measurements have confirmed that the adsorbed CO is formed during CO reduction. However, it still remains ambiguous whether the adsorbed CO is a real intermediate species to produce hydrocarbons or stable poison species. Thus negative polarization of CO adsorbed on Ni electrode was studied by infrared spectroscopy at ambient temperature. 

Infrared spectroscopic measurements on BPO4 catalysts by Moffat and Neeleman and comparison of the spectra with those of similar oxides indicated that surface OH groups exist on BPO4 H20 and H2 exchange confirmed that groups such as 0=P-0H and 0=P may also be present. 

The position, extinction coefficients and band half-widths of anilines and of polycyclic aromatic amines were studied by infrared spectroscopic measurements a long time ago34. One purpose was to understand the hybridization of the nitrogen atom bonded to unsaturated systems35,36. Infrared spectroscopic parameters of the NH2 group in substituted anilines were correlated with the Hammett sigma substituent constants37. 

M. A. Arnold and L. A. Marquardt, Near-Infrared Spectroscopic Measurement of Glucose in a Protein Matrix, Anal. Chem., 65, 3271 (1993). 

K Russell, DC Cole, FM McLaren, DE Pivonka. Analytical techniques for combinatorial chemistry quantitative infrared spectroscopic measurements of deuterium-labeled protecting groups. J Am Chem Soc 118 7941-7945, 1996. 

HCOO" is not reduced at all at a Cu electrode, whereas CO is electrochemically reduced to hydrocarbons and alcohols with a similar product distribution with CO2 reduction (Table 11). " Infrared spectroscopic measurements showed that CO is adsorbed at a Cu electrode at -0.9 to -1.0 V vs. SHE in CO2 saturated electrolyte solution.Ito and his coworkers confirmed the results that linearly adsorbed CO is present on a Cu polyciyslal electrode at... 

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