INVESTIGATION OF ORIENTATIONAL CORRELATIONS AND STRUCTURAL TRANSITIONS IN NEAT LIQUIDS

The temperature dependence of depolarized light scattering intensity (DLSI) and nuclear magnetic resonance (NMR) chemical shift were measured for hexafluorobenzene in the temperature range from 10 to 63-degrees-C. The DLSI curve is not monotone, consists of regions of different slope, and has a dip near 47-degrees-C. The chemical shift curves also consists of different slope straight regions whose separation temperatures are coincident with anomalies on the DLSI curve. As DLSI is directly dependent on effective anisotropy of molecules, the authors suggest that in liquid C6F6, the regions of different slope correspond to molecular structures with different local order and symmetry. The authors derive the conclusion that in liquid C6F6 there are transitions between local structures generated by dimers with small differences between their minimum potential energy.