1. Department of Pharmacy, University of Copenhagen, Copenhagen DK-2100, Denmark
2. Institut Laue-Langevin, CS 20156, Grenoble Cedex 9 38042, France
3. ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, U.K.
4. Department of Physical Chemistry 1, Lund University, Lund SE-221 00, Sweden