Diffusion coefficient rotatory

Fig. 53. Computed decay of the dynamic scattering function for a rather stiff dumbbell according to Ref.215). The rotatory diffusion coefficient is 0, qL = 2, a = L/50, r = 0/2500. L = length of the dumbbell, a2 = mean square amplitude of the bond stretching, r = a2/4 D stretching relaxation time321 ...

In contrast, the motion in the electric field of kinetically rigid molecules for which tq is less than should be governed by the mechanism of the orientation of the molecule as a whole and the rate of this process should be determined by the rotational friction coefficient W or rotatory diffusion coefficient Dj (Eq. (53)). Hence, the study of the orientation kinetics of kinetically rigid macromolecules in the electric field permits the determination of their rotational mobility (i.e. W and Dj). 

Relaxation time r in Eq. (81) is related to the rotatory diffusion coefficient with reject to the axis normal to the dipole of the molecule... 

A similar analysis of the shape of curves Y(Tlrj) for labeled polyamic acid and numberical calculations of the rotatory diffusion coefficients of its units show that the relaxation behavior of a chain is similar to that of a model chain with free internal rotations. This result is in agreement with the data on other conformational and hydrodynamic properties of PAA ° and with theoretical conformational... 

Figure 7 rept uces some results obtained for a sample of ethyl cellulose in benzene which ow how the low frequency polarization varies with G at different substrate concentrations its dependence extrapolated to infinite dilution, and the theoretical behaviour for differing axial ratios of cdl (r) and rotatory diffusion coefficients ( >). The technique can resolve differing relaxation modes in terms of their... 

Taking into account the hydrodynamic interactions between the elements of a worm-like chain, as in the calculation of trandation ffietfon and visosity 62,63) Hearst ) has obtained an expression for the coefficient of rotatory diffusion Dr of the molecule with respect to the central axis normal to its axis of symmetry (axis X or Y in Fig. 11). For the limiting cases of a short and long worm-Uke chain this expression is given by... 

For a solution of kinetically rigid particles (molecules) identical in size and shape, the characteristic orientation angle is uniquely related to coefficients of rotatory diffusion Dj and rotational friction W of a particle... 

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