Spectra for bulk

Although there are no examples of wrell-resolved fine-structure spectra for surface complexes, polycrystaliine spectra for bulk species have been... 

Fig. 13.Temperature dependence of 2H NMR spectra, for bulk PEO and for PEO intercalated in Li+ fluorohectorite. Adopted from [13].

Fig. n.i7. Valence band spectra experimental (solid circles) and calculated spectra (solid line) for (a) bulkZnS, (b) 3.5 nm nanoc stals, (c) 2.5 nm nanoc stals, and (d) 1.8 nm nanocrystals. The calculated spectra for bulk... 

Figure C2.17.10. Optical absorjDtion spectra of nanocrystalline CdSe. The spectra of several different samples in the visible and near-UV are measured at low temperature, to minimize the effects of line broadening from lattice vibrations. In these samples, grown as described in [84], the lowest exciton state shifts dramatically to higher energy with decreasing particle size. Higher-lying exciton states are also visible in several of these spectra. For reference, the band gap of bulk CdSe is 1.85 eV.

Figure 2 Surface EXAFS spectra above the Pd L edge for a 1.5 monolayer evaporated film of Pd on Sid 11) and for bulk palladium ailicide, Pd2Si and metallic Pd.

When Ca and K are added to y-A203 the a parameter does not change. No new additional peaks appear in the spectra for cation concentrations up to 20 at.%. This shows that K and Ca cations do not diffuse into the alumina bulk... 

Further spectroscopic experiments were carried out with an operating reactor using a bed of 1-mm catalyst beads [13]. A 3D experiment with one spectral and two spatial coordinates was carried out, yielding NMR spectra for each pixel of a 2D axial slice. Figure 5.4.7 shows several representative spectra selected from the entire data set. The NMR spectra of neat AMS [Figure 5.4.7(d)] and cumene [Figure 5.4.7(f)] are provided for comparison, they were experimentally detected for bulk liquid samples (lower traces with narrow lines) and their lines were then mathematically broadened to 300 Hz (upper traces) to account for the broadening in the... 

Fig. 5.4.7 (a-c, e) Spatially resolved NMR spectra detected during AMS hydrogenation in a catalyst bed of 1-mm beads. Each spectrum corresponds to a voxel size of 2 x 0.17 x 0.33 mm3. Spectra in (a-c) correspond to the same radial position within the operating reactor and are detected in the top, middle and bottom parts of the reactor, respectively. Three spectra in (b, e) correspond to the same vertical position in the operating reactor, with the two spectra in (e) corresponding to voxels shifted by 1.3 mm to ether side of the voxel of the spectrum in (b). The two spectra in (e) are shifted vertically relative to each other for better presentation. The lower traces with narrow lines in (d, f) are experimental spectra detected for bulk neat AMS (d) and cumene (f), the upper traces in (d, f) were obtained by mathematically broadening the lines to 300 Hz. 

Spectra for a series of Cu-Ni alloys have been obtained (91) and these are reproduced in Fig. 11. Because of overlapping of peaks from the component metals, separate indications of each element are only obtained from the 925 eV Cu peak and the 718 eV Ni peak. The results have only qualitative significance because the quoted nickel concentrations are bulk values. Nevertheless, they do suggest that for these particular samples of Cu-Ni alloys, the surface composition varies smoothly from pure copper to pure nickel. Auger spectroscopy has subsequently shown that the surface composition of the (110) face of a 55% Cu-Ni crystal was identical with the bulk composition (95a). Ono et al. (95b) have used the technique to study cleaning procedures argon ion bombardment caused nickel enrichment of... 

Figure 2. Normalized EXAFS spectra for (A) bulk [Ru (v-bpy)3]+, (B) platinum electrode modified with 5...

A set of SER spectra for adsorbed azide on silver, obtained for the same surface and solution conditions and for a similar sequence of electrode potentials as for the PDIR spectra in Figure 1, is shown in Figure 2. (See the figure caption and reference 7 for experimental details.) Inspection of these SER spectra in comparison with the PDIR results illustrate some characteristic differences in the information provided by the two techniques. Most prominently, in addition to the Nj" j/as band around 2060 cm"1, the former spectra exhibit three other features at lower frequencies attributable to adsorbed azide vibrations. By analogy with bulk-phase spectra for free and coordinated azide (15), the 1330 cm"1 SERS band is attributed to the N-N-N symmetric stretch, vt (2). The observation of both i/a and j/aa features in the SER spectra differs from the surface infrared results in that only the v band is obtained in the latter (2). The appearance of the vn band in SERS is of interest since this feature is symmetry forbidden in the solution azide Raman spectrum. 

In Figure 1 we show the PM-IRRAS spectra for a Pt electrode exposed to saturated C0/H S0 solutions which contain various concentrations of different organic nitriles. For comparison, we have also included a spectrum recorded in saturated CO/H SO with no added nitrile. The adsorption step was accomplished by pulling the electrode back into the bulk solution and cycling the potential from 0.55 V(SHE) up to 1.15 V, down to 0.0 V, and back to 0.55 V. The spectra were recorded after re-positioning the electrode against the cell window while the potential was held at 0.55 V. 

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