Anisotropic signals

Fig.3 -NMR spectra at different sample orientations. The oriented sample of Fig. 2B was manually tilted in the static magnetic field Bq to acquire spectra at different angles, where 0 = 0° corresponds to the usual alignment of the sample normal parallel to the direction of Bq. The arrows indicate the shift of the anisotropic signals with respect to the isotropic value (dotted line), according to the factor 3(cos - l)/2 as expected for a molecule undergoing fast long-axial rotation about the membrane normal...

Fig. 22. Diffusion weighted spectral series recorded from TA (a) and SOL b). Diffusion sensitizing gradients with /i-values of 0, 250, 500, 1000 and 2000 s/mm are applied parallel (Gy) and perpendicular (G ) to the muscle axis. In contrast to SOL, TA shows clearly anisotropic signal losses. Mean diffusion coefficients of 20 subjects are given in (c).

The =Si-0-0 radicals stabilized on the solid surface are stable up to the temperature 650 K. During further temperature increase their dissociation starts accompanied by a quantitative formation of the =Si-0 radicals and appearance of molecular oxygen in a gas phase. The formation of oxy radicals during this process was controlled by two methods (1) the EPR method (the appearance of a broad anisotropic signal, see Figure 7.16a (2) the photoluminescence method (the growth of characteristic red photoluminescence (/imax = 1.95 eV) under UV irradiation of the sample). Thus, a thermal decomposition of peroxy radicals proceeds according to the scheme ... 

Some time-dependent data are depicted in Fig. 14c,d. From a comparison of model computations with the measured temporal evolution of the induced bleaching (isotropic component, Fig. 14c) as well as the ESA (Fig. 14d) directly related to excited state population, we infer a lifetime of the OH-stretching mode of I) = 8 1 ps for the dissolved ethanol monomers. From the anisotropic signal component measured in the same experimental runs we determine the reorientation time to be ror = 2 0.5 ps at room temperature. 

Figure 24 Transient spectra (anisotropic signal) for to = 0 ps and excitation at the peak position of the OH band at three temperature values 273 K (a), 298 K (b), and 343 K (c). Experimental points the calculated thin lines indicate the analysis of the transient bandshapes (thin full line) in terms of the major spectral components I—III (dash-dotted, broken, long-dashed) with Gaussian shape and a Lorentzian spectral hole contribution (dotted line, b,c) the pump frequencies are indicated in the figure by vertical arrows. 

In contrast to the Mossbauer spectroscopy, EPR did not reveal the characteristic signal of a Fe(IV) species antiferromagnetically coupled to a porphyrin radical. Instead, the anisotropic signal detected at D-band frequency (285 GFIz) indicates formation of a tyrosine radical, ascribed to Y96 based on site-directed mutagenesis (Figure 3b). ... 

In such circumstances, the resulting spectral profile may produce a composite profile containing both isotropic and anisotropic signals. It is rare that the spectra will be completely averaged, and frequently one may only observe distortions to the anisotropic signal (i.e. a broadening of the lines). It is therefore important to consider such effects in some detail. 

Fig. 4 Inversion of the diffraction signal at a pump-probe delay time of 1,650 fs. Left panel difference diffraction curves for the isotropic and anisotropic signal Right panel comparison between the original difference density and the inversion via (59). The upper curve is the original difference density, the other curves are reconstructions with different values of c/max and the damping constant k (see [21] for details). Adapted from [21]...

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