Adsorption spectra

Donor strengths, taken from ref. 207b, based upon the solvent effect on the symmetric stretching frequency of the soft Lewis acid HgBr2. Gutmann s donor number taken from ref 207b, based upon AHr for the process of coordination of an isolated solvent molecule to the moderately hard SbCL molecule in dichioroethane. ° Bulk donor number calculated as described in ref 209 from the solvent effect on the adsorption spectrum of VO(acac)2. Taken from ref 58, based on the NMR chemical shift of triethylphosphine oxide in the respective pure solvent. Taken from ref 61, based on the solvatochromic shift of a pyridinium-A-phenoxide betaine dye. 

The features due to adsorbed water and carbonates observed on the boehmite and y-alumina deserve further attention as they differ from results published by previous investigators. Figure 4 shows a series of difference spectra for adsorption on y-alumina. Spectra were taken after drying the y-alumina at 350 C, cooling to room temperature and carrying out room temperature adsorption. The spectra are the difference of the sample before and after adsorption. Spectrum 4e is the spectrum for the as received alumina differenced with the dried alumina. The positive band at 3400 cm" is due to adsorbed water, and the small negative feature at 3740 cm" is due to isolated hydroxyls on the dried surface. Besides the three... 

The adsorption spectrum of aerosil containing admixture vanadium ions exhibits a maximum within the band 290 - 380 nm which was attributed by authors of [97] to the charge transfer transitions in oxygen-containing complexes of five valance vanadium = O -... 

The resemblance of the photocurrent to the optical adsorption spectrum has suggested the involvement of molecular excited states in the creation of charge carriers. While this resemblance is by no means universally observed, the concept of carrier creation via exciton interactions at or very near the illuminated electrode has become increasingly favored. Many of the data leading to these conclusions have been obtained by the use of pulsed light techniques (6, 7,3). These methods are virtually independent of electrode effects and the subsequent analysis of the transient current has led to considerable advances in the theory of charge transfer in molecular crystals. 

Broad-band IRAS experiments are performed, and the IR adsorption spectrum is deconvoluted using a Doppler - shifted source and the Fourier analysis of the data. This technique is not restricted to surfaces. 

The reduction of organic dye methyl orange (MO) over CdS colloids with the particles size d = 2R - 5 nm has appeared to be a convenient reaction for detail studying the kinetics of photocatalytic processes. This dye is readily reducible with no dimers formation. The MO adsorption spectrum in the pH range of 10-12, practically does not change. This allows simplifying the interpretation of the experiments on redox transformations of MO and considering the reaction of photostimulated reduction of MO as a model one. 

In the two cases, the Ru(II) complexes are six-coordinated, however, the pyridine complex is soluble in water whereas [Ru(Dipy)2L2]Cl2 is insoluble because of a strong intermolecular interaction. The polymeric nature of the ligand manifests itself in a 10 run shift of the adsorption spectrum (in the UV-region) of the macromolecular complex due to lowering its resonance stabilization, differences... 

Apart from the intrinsic interest in the process, there are a number of applications of pressure sintering. We mention two. First, this compaction permits the determination of the spectra of solids which cannot be obtained when the sample is in its usual form. For example, Conway (3) has determined the adsorption spectrum of gadolinium oxide down to 2000 A. A similar study is being made on europium oxide by Nathans (5). 

Fig. 13. FTIR spectra of Hp (Si/Al = 12) upon 1,2,4,5-tetramethylbenzene (durene) adsorption. Spectrum 1 highest coverage of durene. Spectra 2-10 evacuation at 300 K. Spectrum 11 evacuation at 400 K. Spectrum 12 pre-treated HP prior to adsorption. Spectrum 13 durene diluted in a wafer of KBr. In the region 1700-1350 cm spectra 1-11 are plotted in difference with respect to spectrum 12. In the inset the DRS-UV-Vis spectra of durene adsorbed on a non-acidic HP (Si/Al = 210) and on an acidic HP (Si/Al = 12) (dashed and full curves, respectively) are compared with the spectrum of the less basic 1,3,5-trimethylbenzene on HP (Si/Al = 12) (dotted curve). In both FTIR and UV-Vis spectra the fingerprints of H-tetramethylbenzene ion are indicated by an arrow. (Adapted with permission from Bjorgen et al. (750).)...

Specific functional units can be immobiUzed at the center of a dendrimer. In the example depicted in Fig. 3.12, a porphyrin imit is immobihzed in a dendrimer (which is called a dendrimer porphyrin). Because the porphyrin unit is buried deep in the dendrimer structure, the dendrimer porphyrin is a good model of a heme protein. The environment of the dendrimer can be evaluated via the spectral characteristics of the central porphyrin. If the size of the dendrimer is large enough, the adsorption spectrum of the porphyrin shows that it is basically independent of surrounding solvent molecules the central porphyrin is shielded by the dendrimer cage. The structural mobility of the inner part of the dendrimer porphyrin has been evaluated via NMR... 

Figure 12.20 Typical adsorption spectrum for pyridine on a zeolite. Adsorption at I50°C and thermodcsorption by steps up to 350 C (L Lewis, B Bronsicd).

Figure 12.21 Typical adsorption spectrum for pyridine on an alumina. Adsorption at 25 C and thermodesorption by steps up to 350°C.

Shimomura, M., Utsugi, K., Horikoshi, J., Okuyama, K., Hatozaki, O., and Okuyama, N. Two-Dimensional Ordering of Viologen Polymers Fixed on Chai d Surface of Bilayer Membranes A Peculiar Odd-Even Effect on Redox Potential and Adsorption Spectrum. Langmuir 7, 760 (1991). 

Fig. 11. (a) Computed IR adsorption spectrum of D2O. (b) Comparison of the computed IR adsorption spectrum with experiment. The solid line is the computed spectrum, the dashed line is the computed spectrum with Egelstaff quantum corrections, and the inset shows an experimental IR spectrum of H2O. Reprinted with permission from Silvestrelli et al. (1997). 

The principle of the measurement by diffuse reflection of the true absorption spectrum of a finely divided colored solid substance has been worked out by Kortiim (24). The substance is introduced under high dilution (mole ratio = 10 to 10 ) into a very disperse powder (average particle diameter 0.1 p) of a neutral white material, which should scatter unselectively and not absorb light in the spectral region concerned. The true shape of the adsorption spectrum is deduced from... 

Fig. 25. Spectrum of triphenylchloromethane -O-O-O" adsorption spectrum in sulfuric acid solution reflectance spectrum of triphenylchloromethane ad-...

Figure 4. Successive averaged circular dichroism spectra of BSA on quartz (1) solution spectrum (2) adsorption spectrum at 15 min and (3) adsorption spectrum at 6 h.

FSM-16, which may be due to the dominant interaction of nanowires with the inner acidic surface of the FSM-16 pores. The adsorption of hydrogen for Pt nanowires was one or two-orders of magnitude smaller than that for nanoparticles. In the IR carbonyl adsorption spectrum, Pt nanowires gave a weak band at 2080 cm corresponding to journal carbonyls, which was shifted to higher frequency than in the Pt nanoparticles (2060 cm ). This shift may reflect the electron-deficiency of the Pt atoms or the dipole coupling of CO on Pt nanowires in mesopores. ... 

The particularly intense yellow color of sweet white wine is different from that of (even oxidized) dry white wine. Its adsorption spectrum is continuous, with a high maximum at 270 mn and no shoulder at 320 nm, as the hydroxyciunamic acids have been broken down by Botrytis cinerea. Concentration by evaporation of water from grapes affected by noble rot and compounds produced by the action of oxydases are responsible for high absorption in the ultraviolet range. 

The form and the average diameter of the silver nanoparticles were estimated with the use of the scanning electron microscopy EVO-40LYTP (Carl Zeiss) with a system of the -ray microanalysis INCA Energy, XRD-analysis and also on a basis of the adsorption spectrum of the surface Plas-mon resonance [5-7. ... 

Figure 6.1. Adsorption spectrum of the initiator IRGACURE 651 at concentrations of 0.05% (1) and 0.10% (2) by mass. The solvent is chloroform.

A diluted solution of chlorophyll a in dry octane has the characteristic adsorption spectrum shown in Fig. 26. If octane is saturated with water, an additional maximum at 742 nm appears in this wet octane (Fig. 31) [86] that is due to formation of the hydrated ohgomer CHl (H20)j,. When interacting with water, ohgomers of chlorophyll undergo hydration, but this process occurs slowly since it involves breaking of old coordination bonds between chlorophyll molecules in dry octane =C=0... Mg and... 

This distance shrinks as v increases, until it finally disappears entirely. Thus, the vibrational energy cannot surpass a certain limit. If we give the molecule more energy than that limit, it dissociates. This results in the presence of a continuous adsorption spectrum beyond a certain value vum of v, so that the difference = 0, which gives us the value ... 

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