Molecular dynamics of guest molecules in the channels of urea inclusion compounds investigated by means of IQNS spectroscopy

We present a brief discussion of the models describing the reorientational and translational motions of the guest molecules in the channels of urea inclusion compounds in their hexagonal phase. We discuss in particular the methodology employed to analyse the incoherent quasi-elastic neutron scattering profiles. Preliminary new results on the dynamics of n-nonanoic acid guest molecules in urea are presented and compared to the results so far obtained on n-alkane/urea and alpha,omega-dibromoalkane/urea inclusion compounds. These results suggest that the two types of motions of n-nonanoic acid, translations and reorientations, are not correlated at the temperatures investigated.