Peak frequency

Figure Cl.5.8. Spectral jumping of a single molecule of terrylene in polyethylene at 1.5 K. The upper trace displays fluorescence excitation spectra of tire same single molecule taken over two different 20 s time intervals, showing tire same molecule absorbing at two distinctly different frequencies. The lower panel plots tire peak frequency in tire fluorescence excitation spectmm as a function of time over a 40 min trajectory. The molecule undergoes discrete jumps among four (briefly five) different resonant frequencies during tliis time period. Arrows represent scans during which tire molecule had jumped entirely outside tire 10 GHz scan window. Adapted from...

Peak frequency (cup) This is the frequeney that the peak modulus oeeurs. Note that... 

Novotny et al. [41] used p-polarized reflection and modulated polarization infrared spectroscopy to examine the conformation of 1 -1,000 nm thick liquid polyperfluoropropy-lene oxide (PPFPO) on various solid surfaces, such as gold, silver, and silica surfaces. They found that the peak frequencies and relative intensities in the vibration spectra from thin polymer films were different from those from the bulk, suggesting that the molecular arrangement in the polymer hlms deviated from the bulk conformation. A two-layer model has been proposed where the hlms are composed of interfacial and bulk layers. The interfacial layer, with a thickness of 1-2 monolayers, has the molecular chains preferentially extended along the surface while the second layer above exhibits a normal bulk polymer conformation. 

MHz, solvent CDC13 APT and DEPT spectra expansion peak frequency in Hz... 

C gated decoupled spectrum. Expanted multiplets peak frequencies in Hz... 

The peak frequencies, integral intensities, and A j A ratios for stretching and... 

Table 3.1. Calculated IR peak frequencies, integral intensities and A /a ratios for stretching (A...

Figure 5.12 Dependence of peak frequencies in infrared spectrum of glucosamide bolaam-phiphiles NC( )GN-GLC (14) on methylene spacer length n. (a) The CH2 antisymmetric vas and symmetric vs stretching vibrations reveal gauche-included conformation for short chains and an all-trans conformation for longer chains, (b) Amide I and II frequencies show an even-odd effect for n > 10. Reprinted from Ref. 53 with permission of Wiley-VCH.

Compound pH/ Electrode Potential Peak Frequency cm-1 Primary Symmetry Species Description... 

Nicodemus and Tokmakoff [60] have measured the IR line shape in the OT stretch region of dilute HOT in H20. The peak is at 2121 cm 1, and the width is 127 cm 1. They are particularly interested in the scaling as one goes from OH to OD to OT, in terms of the peak frequencies and line widths, and its implications for the appropriateness of using electric field fluctuations to describe line broadening. 

The curve is asymmetrical with a longer tail stretching off towards the more positive values. The mean, median and mode are now separated so that X is nearest the tail of the curve the mode is at the peak frequency and the median is in between the two. This type of distribution can sometimes be made normal by logarithmic transformation of the data. 

As the laser beam can be focused to a small diameter, the Raman technique can be used to analyze materials as small as one micron in diameter. This technique has been often used with high performance fibers for composite applications in recent years. This technique is proven to be a powerful tool to probe the deformation behavior of high molecular polymer fibers (e.g. aramid and polyphenylene benzobisthiazole (PBT) fibers) at the molecular level (Robinson et al., 1986 Day et al., 1987). This work stems from the principle established earlier by Tuinstra and Koenig (1970) that the peak frequencies of the Raman-active bands of certain fibers are sensitive to the level of applied stress or strain. The rate of frequency shift is found to be proportional to the fiber modulus, which is a direct reflection of the high degree of stress experienced by the longitudinally oriented polymer chains in the stiff fibers. 

Peak frequencies and Isotope shifts In cm . Isotope shifts with... 

The first case with relatively low-combustor output was investigated in detail to better understand the physical processes involved. Figure 21.7 shows the pressure oscillation amplitude at the peak frequency that was measured as a function of overall equivalence ratio ( ) and the secondary fuel injection frequency. Strong pressure oscillations at 35 Hz were observed in the vicinity of the lean-mixture flammability limit. The oscillation amplitude was particularly strong when the injection frequency was between 32 and 38 Hz. The oscillation frequency often shifted toward the injection frequency, but it was not always identical to the injection frequency. 

Laboratory of Japan, the peak frequency of the floor vibration is at 180 Hz see Fig. 10.3. To achieve atomic resolution, an overall transfer function of 10 or better is needed. 

Genzel and Martin (1972, 1973) measured extinction by MgO smokes loosely packed on transparent substrates both in air and covered with the transparent oil Nujol. Their results showed absorption bands appreciably shifted from the bulk absorption band the peak frequencies agreed with calculations, but the widths were consistently greater than predicted by sphere theory. In addition, a narrower absorption feature always appeared at the... 

Liquids. For a long time, the study of infrared absorption by liquids and solutions has been a convenient way of determining rotovibrational spectra. The goal has often been to just determine peak frequencies, without paying much attention to the band shapes. In more recent years, attention has been devoted to a study of the shapes of vibrational bands and the dynamics of the molecules in the liquid. Only a crude understanding of the dynamics exists which is based on often highly simplified models of real liquids. 

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