Molecular dynamics photon correlation spectroscopy studies

Obviously, in the case of PS these discrepancies are more and more reduced if the probed dimensions, characterized by 2ti/Q, are enlarged from microscopic to macroscopic scales. Using extremely high molecular masses the internal modes can also be studied by photon correlation spectroscopy [111,112], Corresponding measurements show that - at two orders of magnitude smaller Q-values than those tested with NSE - the line shape of the spectra is also well described by the dynamic structure factor of the Zimm model (see Table 1). The characteristic frequencies QZ(Q) also vary with Q3. Flowever, their absolute values are only 10-15% below the prediction. 

Studying molecular orientational order in soft materials, providing information on the ordering of specific bonds. The intensity of the Raman scattered radiation depends on the orientation of the chemical bond with respect to the polarization direction of the radiation. Raman microscopy is used to obtain information on the orientation of molecules at a surface, by scanning a Raman microprobe across it. Photon correlation spectroscopy is usually understood to refer to visible radiation, but the same method can be used to analyse the fluctuations of Raman (and IR) radiation. This provides information on the dynamics of molecular motions, since molecular rotation will modify the vibrational frequencies. This can be used to determine rotational diffusion coefficients. 

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