Relaxation time, conductive liquids, data

Relaxation time (TJ measurements were made on the KjCgo line in sample II between 133 K and 363 K (Fig. 4). For T < 273 K, the Ti data can be fit to the form TjT = K, as expected for a metal (16), with K = 140 K-s. This result provides experimental evidence that molecular orbitals on Cgo molecules contribute to the conduction band in K3 60) as anticipated, and that the normal state of KjC o is a Fermi liquid. Above 273 K, Tj T is reduced. We also see an increase in the NMR linewidth, from 15 ppm to 100 ppm, with decreasing temperature in the range from 300 K to 220 K. We therefore attribute the reduction in T T above 273 K to a contribution to the spin-lattice relaxation rate from rotation of C o ions (9, 13), which vanishes when the rotational motion freezes out and the line broadens. Using K = 140 K-s and the standard... 

The modulus formalism is being applied more frequently to fit data of systems largely influenced by conductivity, such as composites [154], semi-crystalline polymers [143], ionic liquids [63] and biological systems [138]. This allows a better resolution of relaxation processes and leads to similar shape parameters and temperature dependence of relaxation times to those achieved by using complex permittivity [143]. 

Relaxation dispersion data for water on Cab-O-Sil, which is a monodis-perse silica fine particulate, are shown in Fig. 2 (45). The data are analyzed in terms of the model summarized schematically in Fig. 3. The y process characterizes the high frequency local motions of the liquid in the surface phase and defines the high field relaxation dispersion. There is little field dependence because the local motions are rapid. The p process defines the power-law region of the relaxation dispersion in this model and characterizes the molecular reorientations mediated by translational displacements on the length scale of the order of the monomer size, or the particle size. The a process represents averaging of molecular orientations by translational displacements on the order of the particle cluster size, which is limited to the long time or low frequency end by exchange with bulk or free water. This model has been discussed in a number of contexts and extended studies have been conducted (34,41,43). 

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