| Numéro |
J. Phys. I France
Volume 3, Numéro 4, April 1993
|
|
|---|---|---|
| Page(s) | 987 - 1006 | |
| DOI | https://doi.org/10.1051/jp1:1993179 | |
DOI: 10.1051/jp1:1993179
J. Phys. I France 3 (1993) 987-1006Orientational disorder in
P. Schiebel1, A. Hoser1, W. Prandl1, G. Heger2 and P. Schweiss2
1 Institut für Kristallographie, Universität Tübingen, D-7400 Tübingen, Germany
2 Laboratoire Léon Brillouin, CEA-CNRS Saclay, F-91191 Gif-sur-Yvette Cedex, France
61.12-61.50
© Les Editions de Physique 1993
J. Phys. I France 3 (1993) 987-1006
Orientational disorder in
. Evidence for rotation-translation coupling
P. Schiebel1, A. Hoser1, W. Prandl1, G. Heger2 and P. Schweiss2
1 Institut für Kristallographie, Universität Tübingen, D-7400 Tübingen, Germany
2 Laboratoire Léon Brillouin, CEA-CNRS Saclay, F-91191 Gif-sur-Yvette Cedex, France
(Received 30 September 1992, accepted in final form 16 November 1992)
Abstract
Patterson and Fourier analysis of neutron diffraction data of cubic Ni(HN
3)
6I
2 taken at
T = 295 K and
T = 35 K show a planar proton density distribution with four maxima at the corners of a square. We show that this observation is
the consequence of a coupled rotational-translational motion of the NH
3 group in a two-dimensional anharmonic single particle potential with tetragonal symmetry. Our potential ansatz gives a better
fit to the data than conventional crystal structure analysis.
61.12-61.50
© Les Editions de Physique 1993