OH stretching region

Plutonium(IV) polymer has been examined by infrared spectroscopy (26). One of the prominent features in the infrared spectrum of the polymer is an intense band in the OH stretching region at 3400 cm 1. Upon deuteration, this band shifts to 2400 cm 1. However, it could not be positively assigned to OH vibrations in the polymer due to absorption of water by the KBr pellet. In view of the broad band observed in this same region for I, it now seems likely that the bands observed previously for Pu(IV) polymer are actually due to OH in the polymer. Indeed, we have observed a similar shift in the sharp absorption of U(0H)2S0ir upon deuteration (28). This absorption shifts from 3500 cm 1 to 2600 cm 1. 

When the gibbsite is dehydrated a structural collapse occurs with a large increase in surface area. The boehmite sample has a nominal surface area of 325 m /g. The infrared spectrum of the boehmite shows distinct structure in the OH stretching region, with two peaks located at 3090 and 3320 cm". There are three features at 1648, 1516 and 1392 cm" that are due to adsorbed water and carbonate, which are removed upon heating the boehmite to 350 0 in hydrogen. 

Fig. 4 a IR spectra, in the OH stretching region, of from top to bottom, TS-1 samples (full line spectra) with increasing Ti content, from 0 (silicalite-1, dashed spectrum) to 2.64 atoms per imit cell. All samples have been activated at 120 °C. Adapted from [24] with permission. Copyright (2001) by the ACS. b Schematic representation of the preferential location of Ti atoms and Si vacancies in the MFI framework (upper part) and their interplay (lower part). Yellow and red sticks represents Si and O of the regular MFI lattice blue balls refer to Ti, and red and white balls to O and H of defective internal OH groups... 

FigureS.6 CVobtained with a sweep rate ofSOmVs (solid line) and potential dependence of integrated SFC intensity in the OH-stretching region ( ) ofa Pt thin film electrode in 0.1 M HCIO4 solution.

In conclusion, electrochemical SFG measurements showed that the SFG spectra in the OH-stretching region (2800-3800cm ) at the Pt electrode in a 0.1 M HCIO4... 

Figure 5.14 shows SFG spectra in the OH-stretching region (2800-3800 cm obtained at a quartz surface in water before (a) and after (b-f) the contact of PVA... 

The structure of water at the PVA/quartz interface was investigated by SFG spectroscopy. Two broad peaks were observed in the OH-stretching region at 3200 and 3400 cm , due to ice-like and liquid-like water, respectively, in both cases. The relative intensity of the SFG signal due to liquid-like water increased when the PVA gel was pressed against the quartz surface. No such increase of the liquid-like water was observed when the PVA gel was contacted to the hydro-phobic OTS-modified quartz surface where friction was high. These results suggest the important role of water structure for low friction at the polymer gel/solid interfaces. 

Figure 11 Mid-infrared transmission spectra recorded from a linear (high-density) polyethylene before, during and after oxidation at 145°C (a) OH stretching region, (b) carbonyl stretching region. Reproduced from Luongo [23]. Copyright 1960 John Wiley Sons, Inc.

The infrared spectra of EDTA-dealuminated Y zeolites show bands in the OH stretching region similar to those encountered in HY zeolites at about 3750, 3640 and 3540 cm (50,54). However, the OH groups responsible for the 3640 and 3540 cm bands in the spectra of the aluminum-deficient zeolites... 

Figure 4.33 IR spectrum of a dehydrated H,Na-Y zeolite in OH stretching region. (Reprinted from Introduction to Zeolite Science and Practice, Studies in Surface Science and Catalysis, Vol. 58, J.H.C. van Hooff, J.W. Roelofsen, Techniques of Zeolite Characterization, pp. 241-283. Copyright 1991. With permission from Elsevier.)...

M. V. Vener and J. Sauer, Vibrational spectra of the methanol tetramer in the OH stretch region. Two cyclic isomers and concerted proton tunneling. J. Chem. Phys. 114, 2623 2628 (2001). 

In addition to the effects of motional narrowing, vibrational line shapes for the OH stretch region of water are complicated by intramolecular and intermolecular vibrational coupling. This is because (in a zeroth-order local-mode picture) all OH stretch transition frequencies in the liquid are degenerate, and so the effects of any... 

Now suppose that the system of interest has N vibrational chromophores whose frequencies are in the same region, all of which need to be treated quantum mechanically. Such, for example, is the situation for the OH stretch region of... 

It is more difficult to perform ultrafast spectroscopy on neat H20 (than it is on H0D/D20 or HOD/H20) since the neat fluid is so absorptive in the OH stretch region. One innovative and very informative technique, developed by Dlott, involves IR pumping and Raman probing. This technique has a number of advantages over traditional IR pump-probe experiments The scattered light is Stokes-shifted, which is less attenuated by the sample, and one can simultaneously monitor the populations of all Raman-active vibrations of the system at the same time. These experimental have been brought to bear on the spectral diffusion problem in neat water [18, 19, 75 77],... 

Table 2. Positions and FWHM of gaussian sub-bands in the OH stretching region of H2O...

As shown in the figures, the spectral contour in the OH stretching region can be represented as the sum of contribution from four Gaussian components. Since... 

Table 5. Temperature variation of Gaussian component parameters in the OH stretching region of amorphous solid H2O and in the OD stretching region of amorphous solid DsO8...

Given the nature of the Raman spectrum in the OH stretching region, and the fact that the spectral decomposition used is not unique, any set of assignments for the several components must be considered tentative. The following, based on a "common sense analysis, seems reasonable ... 

The most difficult to interpret of the available evidence is the nature of the vibrational spectra of the OH stretching regions of H20(as) and liquid H20. This particular subject is a minefield littered with conflicting opinions and sometimes emotionally held positions. I do not pretend that the following discussion is definitive, but I think it is consistent with the other information available to us. 

We now return to the analysis of the decomposition of the HzO(as) vibrational spectrum in the OH stretching region. It should be made clear to the reader that what follows is highly speculative the "results will be of use, however. 

It will not have escaped the reader s notice that Walrafen s analysis 39> of the OH stretching region of the vibrational spectrum of the liquid also uses a... 

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