Frequency dynamic scattering

Kamada K, Ueda M, Ohta K, Wang Y, Ushida K, Tominaga Y. Molecular dynamics of thiophene homologues investigated by femtosecond optical Kerr effect and low frequency Raman scattering spectroscopies. J Chem Phys 1998 109 10948-10957. 

Dynamical Aspects of Water by Low-frequency Raman Scattering... 

In practice the computerized data reduction procedure consists of the series of steps listed in Table I. For both multimodal resonant frequency data and constant frequency dynamic taken at several different frequencies, the correct value of the reference temperature (Tq) is that which reduces the scatter of the modulus and loss tangent data to fit a smooth curve. The initially assumed value of T0 is taken as the temperature corresponding to the loss tangent maximum or Tg. If this value of T0 does not give satisfactory superposition, the assumed value of T0 is adjusted to a slightly higher value and the procedure is repeated until a satisfactory superposition is achieved. Previous... 

We have so far discussed only materials of negative dielectric anisotropy. Electrohydrodynamic distortions are observed even in weakly positive materials,but only when the initial orientation of the director is perpendicular to the applied field. Striations appear above a threshold voltage but vanish at still higher voltages and there is no dynamic scattering. The frequency dependence of the threshold voltage is shown in fig. 3.10.6. 

The time-dependent mean square displacement can be obtained from the incoherent scattering measurements. It is also pointed out that the frequency-dependent mean square displacement can be obtained from the incoherent dynamic scattering law within the Gaussian approximation. 

In this experiment, we observed dynamics in the frequency region hence, the incoherent elastic scattering intensity of dynamic scattering law S Q,

Y. Tominaga and S. M. Takeuch, Dynamical stmeture of water in dioxane aqueous solution by low-frequency Raman scattering. J. Chem. Phys., 104 (1996), 7377-7381. 

Keeping in mind possible caveats with respect to the interpretation of the results inferred from the extended Drude model, we find that this approach to the data analysis is extremely fruitful and provides important insights into the charge dynamics in cuprates. It is instructive to examine the behavior of the frequency-dependent scattering rate and of the effective mass within simple models. Here we restrict ourselves to one model developed... 

Static and dynamic scattering techniques are spectroscopic characterisation methods in the sense of Sect. 2.2. These techniques evaluate the functional dependency of measurement signals on a spectral parameter, i.e. on time, space, or classically on wavelength or frequency. The major advantage of spectroscopic methods is the reduced sample preparation (no fractionation), but they involve the inversion problem. That is, the spectrum is a—most frequently incomplete and discrete— nonlinear projection of the size distribution. Beside the scattering techniques, there are further spectroscopic methods which are based on the extinction of radiation or on any other response of the particle system to an external field. This section describes optical, acoustic, and electroacoustic methods that have gained relevance for the characterisation of colloidal suspensions. 

The application of a high-frequency electric field to the electrodes induces a transition from the turbid focal-conic texture to the transparent planar texture. This effect is used to erase the light-scattering state obtained after the application of a constant or low-frequency electric field to the cell in the dynamic scattering storage effect described in Section 6.3. 

Light valves were first produced on the basis of the classical semiconductors, ZnS, CdS, ZnSe, CdTe, and GaAs, in contact with nematic or chiral nematic liquid crystal [18]. The basic effects in liquid crystals included electrically controlled birefringence, dynamic scattering, and the cholesteric-nematic phase transition with the frequency response limited to a few Hertz. 

When a.c. fields are used to study Williams domains or dynamic scattering, the frequency must be lower than the limiting frequency f = (27rr) in order to allow... 

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