Microscopic origin of the nonexponential dynamics in a glassy crystal.
The origin of the slow relaxation and of the dynamic heterogeneity is studied for an orientation-ally disordered crystal, orthocarborane, composed of quasi-icosahedrally shaped molecules. Multidimensional deuteron magnetic resonance reveals that large jump angles dominate their complex, anisotropic reorientational motion. It involves a sequence of small-angle tilts about locally preferred axes as well as symmetry adapted threefold jumps. The intrinsic dynamics of this glassy crystal is nonexponential and can be fully accounted for in terms of the tilt and jump motion.
Winterlich
M
M
Experimentelle Physik III, Universität Dortmund, 44221 Dortmund, Germany.
Diezemann
G
G
Zimmermann
H
H
Böhmer
R
R