Spherical domains containing 250 molecules at random positions are shown. The arrows denote the polar axis for each molecule, and the molecules exhibit perfect (a) radial ( ), (b) polar ( ), or (c) azimuthal ( ) orientational order about the Y symmetry axis. Domains in liquid water with R = 20 nm would contain 106 molecules.
Polarization ratios (a) I VV /I HV , (b) I HV /I VH , and (c) I HH /I VH for spherical domains with azimuthal molecular orientation correlations. The solid curves show results from Eqs. (19a)–(19d) for perfectly ordered C ∞v molecules with Kleinman symmetry (u = v = β zxx /β zzz = β xxz /β zzz ) plotted as functions of u. The dashed curves show results from Eqs. (29a)–(29c) for molecules with statistical correlations and arbitrary symmetry plotted as functions of u 1, where for effective β is given by Eqs. (24a)–(24c) . In this case, deviations from u 1 = 1/3 indicate deviations from Kleinman symmetry. Results for the perfectly ordered and statistical distributions agree only for u = u 1 = 1/3, shown by the dotted lines.
Polarization ratios (a) I VV /I HV and (b) I HV /I VH measured with 0.3 or 60 cm−1 spectral bandwidth for solutions of p-nitroaniline (PNA) in acetone-d6 for PNA concentrations up to 1.7 mol/l are shown by the open circles. 12 The solid curves are fits as described in Ref. 12 , with the incoherent contribution to the HRS signal determined from the zero concentration limit for the data, and I VV /I HV = 7.53 and I HV /I VH = 2.00 for the coherent contribution.
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