Long-range orientation correlation in dipolar liquids probed by hyper-Rayleigh scattering

David P. Shelton
2015 Journal of Chemical Physics  
Hyper-Rayleigh scattering (HRS) is sensitive to long-range molecular orientation correlation in isotropic liquids composed of dipolar molecules. The correlation functions that appear in the calculation of HRS mediated by the vector part of the first hyperpolarizability β are the same as the correlation functions for the homogeneous isotropic random vector fields that appear in the description of fluid turbulence. Recent experiments measuring the angle and polarization dependence of HRS from
more » ... r find a dominant transverse mode contribution with amplitude independent of the scattering wavevector, and this observation of transverse mode HRS strongly constrains the form of the orientation correlation function. Analysis of these HRS results for water determines that the long-range molecular orientation correlation function varies as r −3±ε with |ε| < 0.03 on spatial scales up to 2000 nm. C 2015 AIP Publishing LLC. [http://dx.
doi:10.1063/1.4931973 pmid:26450319 fatcat:4a4vmf3m55afxf7i5oiuvnenwi