We have investigated the dynamics of ferrocene in the channels of single crystals of AlPO(4)-5, using nuclear forward scattering. Around 150 K, rotational dynamics sets in, which is strongly anisotropic up to 235 K. Assuming planar rotation of the ferrocene molecules within the channels we obtained an activation energy of (8.2+/-1.0) kJ mol(-1). Between 235 K and room temperature, the rotation becomes isotropic.
(c) 2005 American Institute of Physics.