Vibration OH stretching

Here, we demonstrate the usefulness of SFG spectroscopy in the study of water structure at electrode/electrolyte solution interfaces by showing the potential dependent SFG spectra in the OH-stretching vibration region at a Pt/thin film electrode/0.1 M HGIO4 solution interface in internal reflection mode. 

Broad and diffuse absorption due to the OH stretching vibration of the carboxylic acid. 

T. Ebata, T. Walanabe, and N. Mikami, Evidence for the cyclic form of phenol trimer Vibrational spectroscopy of the OH stretching vibrations of jet cooled phenol dimer and... 

Figure 13.7 Infrared spectra of the OH-stretching vibrations of Bronsted acid sites over FER during adsorption of n-butane at 333°K [5].

A homoleptic bulky a,y-diketonate yttrium complex (fod = 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionate) was immobihzed on MCM-41.280 ( s = 1140m g, Vp = 0.93 cm g, dp = 2.7 nm) and a monopodaUy anchored surface species 6 has been proposed (Scheme 12.5). As suggested by FTIR (strong band for the Si-OH stretch vibration) as well as metal and carbon analysis (circa 3.4 wt% Y, fod/Y circa 2) only around half of the silanol population has been consumed [110]. 

The complexity of the physical properties of liquid water is largely determined by the presence of a three-dimensional hydrogen bond (HB) network [1]. The HB s undergo continuous transformations that occur on ultrafast timescales. The molecular vibrations are especially sensitive to the presence of the HB network. For example, the spectrum of the OH-stretch vibrational mode is substantially broadened and shifted towards lower frequencies if the OH-group is involved in the HB. Therefore, the microscopic structure and the dynamics of water are expected to manifest themselves in the IR vibrational spectrum, and, therefore, can be studied by methods of ultrafast infrared spectroscopy. It has been shown in a number of ultrafast spectroscopic experiments and computer simulations that dephasing dynamics of the OH-stretch vibrations of water molecules in the liquid phase occurs on sub-picosecond timescales [2-14],... 

Fig.l. (a) Experimental TG signal (solid line) and amplitudes of its additive components chromophore response (open circles) and solvent response (open squares) as found from the analysis of heterodyne-detected TG data. Inset the phase of the TG signal, (b) Experimental EPS data for the fixed delays to (empty circles) and t23 (solid circles), and the theoretical simulations (lines). Inset the excitation pulse spectra (shaded contour) and the absorption spectrum of the OH-stretch vibration of HDO molecules in D2O (dashed line). 

The EPS experiments were carried out according to the procedure described in Ref. [20], The sample, used in experiments, was a 0.6 M solution of HDO molecules in heavy water at room temperature (maximal OD-O.6). The solution was pumped through a sapphire nozzle to form 100-pm thick, free-standing jet, that was positioned at the intersection of the laser beams. Use of the free-standing jet instead of a sample cell allowed us to avoid unwanted complications such as temporal broadening of the ultrashort pulses, their adverse scattering, and cross-phase modulation. The excitation pulses were -70 fs in duration and centered around -3 tm [19]. The excitation pulse spectra and the absorption spectrum of the OH-stretch vibration of HDO molecules in D2O are shown in the inset to Fig.lb. 

The TG signal of the OH-stretch vibrational mode of HDO molecules dissolved in D2O is shown in Fig. la by a solid line. The initial part of the signal decays with a time constant of-700 fs that is consistent with the population lifetime [4]. However, after reaching a minimum around 2 ps the TG signal begins to grow and finally levels-off at —10 ps. 

The band observed at 3745 cm"1 is similar in frequency to that of silanol groups in silica, and Angell and Schaffer (147) attributed it to a Si-OH-stretching vibration. No structural position was assigned with certainty, although it possibly arises from siliceous material occluded within the zeolite structure. It has also been ascribed to Si-OH groups terminating the zeolite framework. 

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