On the theory of light scattering in molecular liquids
Institut für Physik, Johannes-Gutenberg Universität, 55099
Revised: 7 November 2000
Published online: 15 February 2001
The theory of light scattering for a system of linear molecules with anisotropic polarizabilities is considered. As a starting point for our theory, we express the result of a scattering experiment in VV and VH symmetry as dynamic correlation functions of tensorial densities with l=0 and l=2. l, m denote indices of spherical harmonics. To account for all observed hydrodynamic singularities, a generalization of the theory of Schilling and Scheidsteger  for these correlation functions is presented, which is capable to describe the light scattering experiments from the liquid regime to the glassy state. As a microscopic theory it fulfills all sum rules contrary to previous phenomenological theories. We emphasize the importance of the helicity index m for the microscopic theory by showing, that only the existence of m=1 components lead to the well known Rytov dip in liquids and to the appearance of transversal sound waves in VH symmetry in the deeply supercooled liquid and the glass. Exact expressions for the phenomenological frequency dependent rotation translation coupling coefficients of previous theories are derived.
PACS: 64.70.Pf – Glass transitions / 78.35.+c – Brillouin and Rayleigh scattering; other light scattering / 64.70.Dv – Solid-liquid transitions / 61.25.Em – Molecular liquids
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001