Doppler shift, in light scattering

Doppler shifts in light scattering from macroion in solution. 

M. J. Stephen. Doppler shifts in light scattering from macroions in solution. J. Chem. Phys., 61 (1974), 1598-1599. 

Pecora, R., Doppler Shifts in Light Scattering from Pure Liquid and Polymer Solutions, J. Chem. Phys., 1964,40, 1604-1614. 

Electrophoretic instruments for analysis of colloidal suspensions can be divided into two basic classes optical instruments for which the operator observes the migration of particles in a field using a microscope and laser-based instruments that measure the Doppler shift in the frequency of the scattered light from particles... 

In dynamic light scattering experiments the motion of a particle with constant velocity results in a Doppler shift in the frequency spectrum. In a heterodyne experiment (mixing of a small portion of the unscattered light with the scattered one on the photomultiplier) this shift Aw can be directly determined from the power spectrum [98], providing the electrophoretic mobility by the simple relation... 

In many technical problems in hydrodynamics or aerodynamics, the velocity profile v(r,t) of a flowing medium in pipes or around solid bodies is of great importance. Doppler anemometry (Sect. 7.12) is a heterodyne laser spectroscopy technique where these velocity profiles are determined from the measured Doppler shifts of the scattered light [1503-1505]. The beam of a HeNe or Ar laser with wave vector A l passes through a volume element dV of the flowing medium. The frequency co of light scattered in the direction ks by particles with velocity v (Fig. 10.34) is Doppler-shifted to... 

Fig. 6. Diagrams for the calculation of the frequent shift of light scattered from hypersonic sound waves which are thermally excited in liquids. In the top diagram the light is considered to be Bragg reflected from the compressional wave which is moving through the liquid. The frequency shift arises bwause of the Doppler effect. In the second diagram the light photon is considered to be scattered by a sound phonon. By momentum conservation the wave vector of the scattered li t, k must equal the sum of the incident wave vectors of the incident photon, k, and the phonon, X, (third diagram)...

The scattering techniques, dynamic light scattering or photon correlation spectroscopy involve measurement of the fluctuations in light intensity due to density fluctuations in the sample, in this case from the capillary wave motion. The light scattered from thermal capillary waves contains two observables. The Doppler-shifted peak propagates at a rate such that its frequency follows Eq. IV-28 and... 

Laser Doppler Velocimeters. Laser Doppler flow meters have been developed to measure Hquid or gas velocities in both open and closed conduits. Velocity is measured by detecting the frequency shift in the light scattered by natural or added contaminant particles in the flow. Operation is conceptually analogous to the Doppler ultrasonic meters. Laser Doppler meters can be appHed to very low flows and have the advantage of sensing at a distance, without mechanical contact or interaction. The technique has greatest appHcation in open-flow studies such as the deterrnination of engine exhaust velocities and ship wake characteristics. 

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