Rayleigh light scattering spectroscopy

Development of Rayleigh Light Scattering Spectroscopy/Imaging System 561... 

The nature of polymer motion in semidilute and concentrated solutions remains a major question of macromolecular science. Extant models describe polymer dynamics very differently 3-11). Many experimental methods have been used to study polymer dynamics (12). One meAod is probe diffusion, in which inferences about polymer dynamics are made by observing the motions of dilute mesoscopic probe particles diffusing in the polymer solution of interest. Probe diffusion can be observed by several experimental techniques, for example, quasi-elastic light scattering spectroscopy (QELSS), fluorescence recovery after photobleaching (FRAP), and forced Rayleigh scattering (FRS). 

The dynamics of the collective excitations can be determined conveniently by photon autocorrelation spectroscopy, which is also called self-beating, time-resolved Rayleigh or quasi-elastic light scattering spectroscopy [29]. Here the time autocorrelation function of the scattered light intensity G (t) is measured, which, in the heterodyne detection regime, is given by ... 

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. 

A full theory of light scattering from a viscoelastic medium has been presented by Rytov17). This theory has been extensively discussed in the context of Rayleigh-Brillouin spectroscopy of bulk polymers18"21). In the present paper the results of that work will be presented and extended to include relaxation near the glass transition. 

A. V. Sechkarev and P. T. Nikolaenko. Investigation of intermolecular dynamics in the condensed states of matter by the method of vibrational spectroscopy. Part 1 Intensity distribution and intermolecular light scattering spectra in the neighborhood of the Rayleigh line. Izv. Vuz. Fiz. [U.S.S.R.), 4 104-110 (1969). 

Figure 9.6 Elastic and inelastic scattering of incident light by molecules. Rayleigh, elastic scattering Stokes and anti-Stokes, inelastic scattering. (Reproduced from P. Hendra, P.C. Jones, and G. Warnes, Fourier Transform Raman Spectroscopy Instrumentation and Chemical Applications, Ellis Horwood, Chichester, 1991.)...

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