Resonance region

Figure 7.16 When soft pulses are used for excitation and mixing in a 2D experiment, it becomes a 2D soft experiment. The spectrum of the 2D soft experiment has reduced frequency ranges in F, and Fj. The excitation ranges of the selective pulse depend on the type of experiment. For example, in a soft COSY-COSY experiment, one multiplet is excited, while in the soft NOESYexperiment the whole resonance region of a group of signals is excited. (Reprinted from Mag. Reson. Chem. 29, H. Kessler et al, 527, copyright (1991), with permission from John Wiley and Sons Limited, Baffins Lane, Chichester, Sussex P019 lUD, England.)...

Finally, we would like to point out that in the off-resonance region, the response time of the nonlinearity is limited only by the optical pulse width r, as long as (Ea -Tiaj)/h >>2ir(x ). (8) This is no longer true when collisions (or phonons in solids) are present. For optical frequencies close enough to the absorption edge, the collision induced transitions to the excited state will cause the x s response time to be limited by the relaxation time of the excited states. (8)... 

At a fundamental wavelength of 1064 nm, large and anisotropic optical nonlinearity was also observed. The values of X (3) and are 4.5 x 1010 esu and 1.0 x 10 10 esu, respectively. The large values are due to the two photon resonance, because the harmonic wavelength of 355 nm is near off-resonance region. From the two-photon fluorescence measurement, we confirmed that a two-photon absorption band, which is origin of the enhancement effect, exist around 532 nm, half of the fundamental wavelength. 

Figure 11 shows the a carbon resonance region of such a THF/ OXP copolymerization in CH3NO2. At about 55 ppm we observe the peak due to the methoxy methyl carbons of the chain ends, and further downfield a solvent peak and then the methylene carbons of the unreacted monomers, THF and OXP. There are two peaks attributable to the polymeric methylene carbons. The higher field one is due to THF and the other one to OXP. Similarly, two peaks are observed for the methylene carbons attached to the methoxy chain ends. The fact that the intensities of these two peaks are similar indicates that both THF and OXP participate in the initiation step. 

The experiments to search for EDMs in atoms and molecules are carried out using different approaches [40, 6]. The experimental technique depends on the properties of the atoms and molecules used in such an experiment. These properties influence the atomic and molecular sources, resonance region and detector. For example, for diatomic radicals like YbF or PbF the... 

On both sides of the resonance region n increases with increasing frequency, which is called normal dispersion. Only in the immediate vicinity of the resonance frequency does n decrease with frequency, so-called anomalous dispersion. Such a reversal of dispersion, if it occurred in transparent regions, would provide a much-needed material for designing color-corrected lenses. Unfortunately, anomalous dispersion occurs only in regions of high absorption where no appreciable light is transmitted. 

To minimise the friction effect, it has been proposed to use smaller amplitudes and higher frequencies [122,137]. The so-called scanning local-acceleration microscopy (SLAM) is another modification of contact-mode SFM which was implemented by vibrating the sample at a frequency above the highest tip-sample resonance (region III in Fig. 13b). In this frequency range (around 1 MHz), the cantilever response to the sample excitations becomes independent of the cantilever stiffness and depends linearly on the contact stiffness and reciprocally on the cantilever mass m (Fig. 13b) ... 

E. Engdahl, E. Brandas, Resonance Regions Determined by a Projection-Operator Formulation, Phys. Rev. A37 (1988) 4145. 

Notice that the resonant regions follow the locus of the migrating minima, the trenches that were discussed above, and seem to be pinpointed by the cross-ripple pattern mentioned above. 

Styrene/ethyl acrylate random copolymers were prepared with ethyl acrylate..contents of 10,25,50,75 and 90% by weight. Examination of the 3C NMR spectra of the copolymers reveals that the carbonyl carbon of the acrylate ester is a sensitive probe of the sequence distribution in these copolymers. Figure 2 shows the carbonyl carbon resonance region for a sample containing 50%... 

To determine the nature of the dispersion curve at frequencies between the main dispersion and resonance regions the data contained in references (4-15) at 20 C were combined with the 70GHz values and the permittivity results of Asfar and Hasted up to frequencies less than 2THz. The combined data were then fitted to the equation... 

In the resonance region the system oscillates with the external frequency X and with an increased amplitude (entrainment region). Far away from resonance, the internal free oscillations are present. This behaviour is completely absent in systems, where no self-sustained oscillations can exist. A typical example of such a system is a nonlinear conservative system. The resonance diagram has been drawn in Figure 2 for both, the small and the large ampli tude oscillation. 

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