Oxygen spectra

Figure 5 Oxygen spectra from bulk Si02, a thin film of Si02 on Si, and Si02 under a thin...

Fig. 11. The EPR spectra at 77 K. of OJ on CoO-MgO samples. Spectra (a) and (b) were recorded after evacuation of oxygen at 298 K, (c) and (d) in the presence of a small amount of oxygen. Spectra (a) and (c) refer to a 0.2% CoO-MgO sample, whereas spectra (b) and (d) refer to a 5% CoO-MgO sample (the cobalt concentration is expressed as Co atoms per 100 Mg atoms) (110).

By systematic variation of the chemical composition of these solutions and by applying surface analytical methods, unique information can be obtained from O Is (Fig. 9-41) and Fe 2p3/2 (Fig. 9-42) XPS spectra of the surface layer formed on the test specimens. Comparative analysis of the iron and oxygen spectra proved that HEDP of 10" M, and partly of 10 M concentration, causes a striking decrease in Fe-0 and an increase in the metallic iron ratio. At 10 M concentration, which is the optimal concentration of the protective inhibition effect, the Fe-0 content is 10 times as high as... 

Fig. 4.1 STS profiles of a Cu(llO) surface (reprinted with permission from [4]) and b Nb(llO) surface (reprinted with permission from [5]) with and without chemisorbed oxygen. Spectra in panel a were obtained (A) at a metallic region, (B) on top of, and (C) between protrusions of the Cu chain [11] on the Cu(110)-(2 x l)-0 surface.

Figure 4 (A to C) shows changes in the ESR spectra obtained with D-mannose phenylhydrazone treated with 1% potassium terf-butoxide in methyl sulfoxide. The original three-line pattern (spectrum A), ascribed to the nitroxide radical, rearranges to a new pattern in about 15 minutes (spectrum B) this pattern remains steady for hours if the solution is kept in the absence of oxygen (spectrum C).

The details of the ozone absorption spectrum26-26 are not nearly as well understood as those of the oxygen spectrum. Taube27 has summarized the energetics of the decomposition of ozone and a somewhat more extensive tabulation is presented in Table IV. 

One important chemical result from the ESCA studies involves the formation of surface carboxylates. Upon transfer of the monolayer to silver, the formation of a carboxylate could be detected by the production of a single peak in the oxygen Is line due to equivalent oxygens in the carboxylate structure. Since the oxygen spectrum of the monolayer yields near stoichiometric C-0/C==0 ratio of 1, the carboxylate is not detectable. Studies with monolayer films of cadmium arachidate indicated detectability of the carboxylate as a single carbon Is peak. The lack of the formation of this interfacial carboxylate indicates the strength (or weakness) of surface chemistry which occurs on this silver surface as prepared. 

Figure 5.28 Difference absorption spectra of a non-irradiated original colloidal Zr02 sol and irradiated sol for 60 min at all the UV/visible wavelengths from the hght source (spectrum 1), with methanol present (spectrum 2) and in the presence of oxygen (spectrum 3). Reprinted in part with permission from Emeline et al. (1998b). Copyright (1998) American Chemical Society.

Figure 9.10. Auger election spectra of Ti-5Al-2.5Sn surfaces spectrum a, after impact fracture in vacuum spectrum b, after exposure to 5.3 x 10 Pa-s (4 X 10 torr-s) water vapor spectrum c, after exposure to 5.3 X 10 Pa-s (4 x 10 torr-s) oxygen spectrum d, after exposure to water vapor at 1.33 kPa (10 torr) (Ej, = 2 KeV, 3 eV peak-to-peak, Ip = 20 /xA) [6].

Figure 13.14 Molecular oxygen absorption spectrum over the spectrum of a free-running ArF exciplex laser. The absorption peaks in the molecular oxygen spectrum are Schumann-Runge absorption bands. (Courtesy of R. Kunz and R. Dammel...

Figure 6.19 also indicates an oxygen spectrum characterized by m/e = 32. Weak traces of earbon monoxide and carbon dioxide were also detected but are not presented in this diagram. 

Using a modern spectrometer with better resolution, Figure 7 shows a spectrum of an ordered OF overlayer on Ag(llO) generated by the reaction of water with pre-adsorbed oxygen (the oxygen spectrum is the lower curve in Figure 7). The OH radical is stabilized by the chemisorption bond to the silver surface and forms an ordered (1 x 2) layer. Note that the 8(0- H) mode is broadened relative to the elastic peak, and that phonons due to the silver surface are observed as both losses and gains (45, 83 cm" ). 

The effects of TIP also appear in figure B 1,11.3 and figure B 1.11.4. In the NMR spectrum, all the resonances of the sp carbons lie above 100 ppm (a usefiil general rule of thumb) because A is smaller for multiple bonds. The highest shifts are for the carbonyl C at 169 ppm and the ring C attached to oxygen at 155... 

Tetracyclines are produced by various Streptomyces strains and are extensively applied in human and veterinary medicine. They display a broad spectrum of antimicrobial activity in combination with low toxicity and can be applied orally. The most commonly prescribed tetracycline drugs are tetracycline itself and oxytetracycline, an oxygenated derivative, which are directly isolated from fermentation liquors, and doxycycline whose partial synthesis from oxy-... 

Mass Spectrometry Ethers like alcohols lose an alkyl radical from their molecular ion to give an oxygen stabilized cation Thus m/z 73 and m/z 87 are both more abun dant than the molecular ion m the mass spectrum of sec butyl ethyl ether... 

Section 16 18 An H—C—O—C structural unit m an ether resembles an H—C—O—H unit of an alcohol with respect to the C—O stretching frequency m its infrared spectrum and the H—C chemical shift m its H NMR spectrum Because sulfur is less electronegative than oxygen the H and chemical shifts of H—C—S—C units appear at higher field than those of H—C—O—C... 

In a mass spectrum, the ratios of isotopes give a pattern of isotopic peaks that is characteristic of a given element. For example, the mass spectrum of any corn ound containin carbon, hydrogen, nitrogen, and oxygen will show patterns of peaks due to the, 7C, 7N, gO, gO, and... 

A comparison of the relative basicities of pyrrole, furan and thiophene may be made by comparing the pK values of their 2,5-di-t-butyl derivatives, which were found to be -1.01, —10.01 and —10.16, respectively. In each case protonation was shown by NMR to occur at position 2. The base-strengthening effect of alkyl substitution is clearly apparent by comparison of pyrrole and its alkyl derivatives, e.g. A-methylpyrrole has a pKa. for a-protonation of -2.9 and 2,3,4,5-tetramethylpyrrole has a pK of 4-3.7. In general, protonation of a-alkylpyrroles occurs at the a -position whereas /3-alkylpyrroles are protonated at the adjacent a-position. As expected, electron-withdrawing groups are base-weakening thus A-phenylpyrrole is reported to have a p/sTa of -5.8. The IR spectrum of the hydrochloride of 2-formylpyrrole indicates that protonation occurs mainly at the carbonyl oxygen atom and only to a limited extent at C-5. 

The H NMR spectrum of thiirane 1-oxide is complex (AA BB ) at 60 MHz 24 lines are cfbserved consisting of two sets of 12 centered about a midpoint. The H NMR chemical shift in thiirane 1,1-dioxide is fairly sensitive to solvent variations partly because of the high dipole moment (4.4 D) of the sulfone. The benzene-induced shift, A5 (CeDe-CCLt), is large (-1.04 p.p.m.), as expected from the presence of a sulfone group. Oxygen-17 chemical shifts for thiirane 1-oxide and thiirane 1,1-oxide are -71 and +111 p.p.m. respectively, relative to H2O. 

The individuality of received complexes was proved by X-ray phase analysis (DRON-3.0). Preparative investigation of complexes was made. Infrared spectrums of complexes were made (Uh-20, KBr). It was proved that in the III complex hydroxylamine is coordinated with Fe (II) by oxygen in the form of n-oxyde-o-NH -and in IV - by nitrogen in the form of NH OH. The composition of IV hasn t been proved in dry ruminant because of surplus age of reagent. Tire composition of III responds to formula of [Fe(NH,OH) Cl,]. 

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