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Light-scattering studies of polyelectrolyte solutions without added salt have been made near the transition dilute/semidilute regime. Aqueous solutions of sodium poly(styrenesu1fonate) (molecular weight: 7.8 X lo5) with concentrations from lo-' to 4 X lo-* g/L show a q dependence of both the scattered intensity and the effective diffusion coefficient. The scattered intensity is characterized by a broad peak for q between A-1. This result is similar to those obtained by small-angle neutron-scattering experiments in the concentrated regime. The q value corresponding to the maximum intensity varies as C'I2 for the whole range of concentrations. The diffusion coefficient shows a clear minimum around q values where the maximum in the structure factor ( q M ) is observed. The experimental results are consistent with a short and local ordering due to the long-range Coulombic interactions of slightly flexible chains near the rod limit. and 3 X The pulse radiolysis of benzophenone in liquid 1-propanol was investigated within a large temperature range. At temperatures lower than 180 K the absorption spectrum of benzophenone anion is time dependent. The blue shift observed after the pulse is attributed to the reorientation of alcohol molecules around the aromatic anion which was formed in a presolvated state. The kinetics of this spectral shift was studied as a function of temperature. Comparison with the dielectric relaxation times in 1-propanol shows that the rate-determining step is the breaking of solvent hydrogen bonds. The possibility that part of the spectral shift is due to the formation of a hydrogen bond between the solvent and the anion is discussed.

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