Resonance intensity

Kneubuhl, F.K. and Natterer, B. 1961. Paramagnetic resonance intensity of anisotropic substances and its influence on line shapes. Helvetica Physica Acta 34 710-717. 

When one resonance in an NMR spectrum is perturbed by saturation or inversion, the net intensities of other resonances in the spectrum may change. This phenomenon is called the nuclear Overhauser effect (NOE). The change in resonance intensities is caused by spins close in space to those directly affected by the perturbation. In an ideal NOE experiment, the target resonance is completely saturated by selected irradiation, while all other signals are completely unaffected. An NOE study of a rigid molecule or molecular residue often gives both structural and conformational information, whereas for highly flexible molecules or residues NOE studies are less useful. 

Figure 3 Polarisation dependence of the n resonance intensity at the 0 1s edge for Ni 100 (/2x/2)R45°-C0. Degree of photoionisation, P, of the incident radiation is taken to be 0.85 for the calculated curve. 6 is the angle of tilt of the C-0 axis relative to the surface normal. The analysis assumes no reduction in symmetry from Ca>v.

The peak in the derivative of the 5-phase resonance does not change drastically in intensity upon oxidation. The /8-phase resonance, however, does change considerably in intensity in the intermediate concentration range (0.5-3.6 wt. %) upon oxidation. Upon exposure of reduced chromia-on-alumina samples of low concentration to air at room temperature, a rapid color change from blue to green occurs and the EPR characteristic of the 7-phase immediately appears, although reduced in intensity in comparison to the 7-phase resonance intensity after oxidation at 600°. 

One would expect the presence of trapped electrons in the oxidized samples to give rise to n-type conductivity, conduction possibly taking place by jump migration of the odd electron in the lattice of Cr + ions in a somewhat similar manner to the mechanism discussed by Heikes 174) for the migration of Ni + holes in lithia-doped NiO. The observed p-type conductivity of chromia in an oxygen atmosphere is presumably due to electron holes in a solid which is predominantly CraOs for the low concentrations of chromia-on-alumina where the 7-phase resonance intensity is maximum, the chromium is predominantly in the d-6 valence state 167). 

Such a small crystal behaves like an infinitely expanded crystal. However, if the crystal vibrations remain restricted to the center, one can clamp the outer edge to a crystal holder, without engendering undesired side effects. Moreover, contouring reduces the resonance intensity of undesired anharmonics. This limits the capacity of the resonator to maintain these oscillations considerably. 

Quantum control beyond spectral interference and population control Can resonant intense laser pulses freeze the population ... 

In this contribution recent results [13] on the control of the quantum mechanical phase of an atomic state in strong laser fields studied using the Autler-Townes (AT) effect [14] in the photoionization of the K (4p) state are discussed. We demonstrate quantum control beyond (i) population control and (ii) spectral interference, (i) We show, that for suitable combinations of the laser intensity of the first pulse and the time delay the second resonant intense laser pulse leaves the excited state population unchanged. However, the knowledge of the... 

Solvent effects on the positions of the 14N resonances for pyrrole and indole have been studied indirectly, through observation of the variation in NH proton resonance intensity... 

Fig. 9. Proton NMR spectra at 220 Me of solutions in d5-pyridine of the Zn(II)-complexes with porphin, and the dimethylesters of mesoporphyrin IX, deuteropor-phyrin IX, and protoporphyrin IX. The resonance assignments were based on the relative resonance intensities and the observed fine-structure from spin-spin coupling they agree with previously published data by Caughey and Koski (17 a = ring methyls (for porphin protons at positions 1 to 8), b = mesoprotons, c and d = methylene protons of the propionates, e = methylesters, / and g = resonances of the substituents at positions 2 and 4. Three strong resonances between —7 and —9 ppm come from d5-pyridine, the line at ca. —4.9 ppm from HDO. T = 25 °C...

For linear polymers where "N" is zero, the carbon number and number average molecular weight can be easily and reliably determined. For those polymers containing long chain branching, one must utilize the ratio of the carbon resonance intensities associated with branching to the end group carbon resonance intensities to determine "N" as follows ... 

B. Bleaney, Electron spin resonance intensity in anisotropic substances. Proc. Phys. Soc. (Lond.), 1960, 75, 621-623. 

Because the signal decays as a function of time, while the noise is stationary, data points at the beginning of the FID contribute more to the resonance intensity than do points near the end of the FID. One common way to discriminate against later points with poor S/N without abruptly truncating the FID is to use an exponential filter, with... 

The nuclear Overhauser effect (NOE), which is manifested in certain changes in the intensities of NMR lines, is a consequence of magnetic dipolar relaxation. The name comes from a phenomenon predicted by Albert Overhauser in 1953, when he showed theoretically that saturating the electron magnetic resonance in a metal would cause the nuclear resonance intensity to be enhanced by a factor of the order of 103 (the ratio of "/electron/"/nucleus)- lonel Solomon later found that a similar effect occurs between two nuclei, but with a much smaller intensity enhancement—the nuclear Overhauser effect.90 Because the NOE is of great practical im-... 

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