title: Onset of slow dynamics in difluorotetrachloroethane glassy crystal.
abstract: Complementary neutron spin-echo and x-ray experiments and molecular-dynamics simulations have been performed on difluorotetrachloroethane (CFCl2-CFCl2) glassy crystal. Static, single-molecule reorientational dynamics and collective dynamics properties are investigated. Our results confirm the strong analogy between molecular liquids and plastic crystals. The orientational disorder is characterized at different temperatures and a change in the nature of rotational dynamics is observed. A careful check of the rotational diffusion model is performed using self-angular correlation functions Cl with high l values and compared to results obtained on molecular liquids composed of A-B dumbbells. Below the crossover temperature at which slow dynamics emerge, we show that some scaling predictions of the mode coupling theory hold and that alpha-relaxation times and nonergodicity parameters are controlled by the nontrivial static correlations.
authors.affiliation: Laboratoire de Dynamique et Structure des Matériaux Moléculaires, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 8024, Université Lille 1, 59655 Villeneuve d'Ascq Cedex, France. frederic.affouard@univ-lille1.fr
authors.forename: F
authors.initials: F
authors.lastname: Affouard
authors.forename: E
authors.initials: E
authors.lastname: Cochin
authors.forename: F
authors.initials: F
authors.lastname: Danède
authors.forename: R
authors.initials: R
authors.lastname: Decressain
authors.forename: M
authors.initials: M
authors.lastname: Descamps
authors.forename: W
authors.initials: W
authors.lastname: Haeussler