An inelastic neutron scattering study of the dynamics of the van der Waals complex C₆H₆:C₆F₆

Abstract

The temperature dependence of the dynamics of the van der Waals complex formed between benzene and hexafluorobenzene has been investigated in its solid states. The measurements fall into two regimes. At low temperatures, T ⩽ 1>00 K, using inelastic neutron scattering discrete librational transitions between pairs of molecules have been observed. At higher temperatures, T ⩾ 205 K, we lose this discrete structure and obtain the phonon spectrum. Both sets of spectra are rationalized using relatively simple molecular models.