Sketch of the experimental setup. The light generated by a LED crosses the sample and is scattered into the PM-S. Collimators define the field of view, while a polarizer is used to disentangle different contributions to the scattering amplitude. The PM-B monitors the beam intensity.
Data points in dependence of the scattering angle . Filled (open) circles represent perpendicular (parallel) polarization. The two lines correspond to fits to the data points, parametrized according to Eq. (7). Data correspond to a dodecane sample at 415 nm wavelength.
Results for the anisotropic scattering length for PXE “U,” C12, PC, and CX at three different wavelengths. For comparison, fits according to Eq. (10) are shown as solid curves of the same color. The data points are in good agreement with the -dependence expected for Rayleigh scattering.
Corrections applied to the measured ratio of scattered to incident number of photons: the correction regarding greyfilter and polarizer transmission was measured for three relevant wavelength regions. reflects the relative photoefficiencies of PM-S and PM-B, while corrects for light losses due to reflections at the sample surfaces (Sec. IV).
Overview of the CAS numbers, molecular purities, product names, and manufacturers of the used solvents and solutes.
Results from the measurement series performed at 430 nm. The isotropic , anisotropic , and the total scattering length are reported. For and , only the uncorrelated uncertainties are quoted; for also the correlated uncertainties. The reduced -value of the analysis fit are shown as well. The expected Rayleigh scattering length is shown for comparison (Sec. V A).
Results from the second measurement series performed at three different wavelengths. Anisotropic , isotropic , and the resulting total scattering length are reported for original and purified PXE, C12, PC, and CX. The last column shows the reduced -value of the analysis fit.
Expected values (Refs. 27–33) and best-fit parameters resulting from a fit of Eq. (10) to the measured anisotropic scattering length at three different wavelengths. The values of the absorption-band maximum agree rather well with predictions, while uncertainties are quite large. corresponds to the Rayleigh scattering length at 430 nm. indicates the quality of the fit .
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