Rayleigh-Brillouin light spectrum

This chapter has considered measurements of the dynamic structure factor S q, t) of polymer solutions. Here behaviors of the first cumulant, the polymer slow mode, and the high-frequency Rayleigh-Brillouin spectrum have been considered. Neutron spin-echo methods as supplements to light scattering spectroscopy were noted. Results on Ki and the Rayleigh-Brillouin spectrum are readily summarized. The discussion of the slow mode is considerably more extended, but leads to a comparison with modem models for glass formation. 

When we introduce the definition of (2.27), (2.28) and (2.29) in the correlation function we get the complete response function measured in any light scattering experiment, apart from the II contributions. This response describes the spectrum from the so called Rayleigh-Brillouin to the Raman roto-vibrational scattering. 

Fig. 7. Typical diagram of the spectrum of scattered light as measured by a Fabry Perot interferometer showing the Rayleigh line (center) and the Brillouin doublet. From the frequency shift and the width of the Brillouin bands one can obtain the storage and loss moduli fin- compresacHKil waves exxuring at hypersonic frequencies...

The power spectrum of the light, scattered from the ice-water interface at conditions close to equilibrium, contains only Raman and Brillouin contributions. There is no Rayleigh scattering. At a critical growth rate an onset of quasi elastic light scat-... 

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