Observed for the first time, using incoherent quasi-elastic neutron scattering, a diffusive motion of a molecular unit intercalated in graphite in which both rotational and translational components were present. In the semi-incommensurate phase only a rotational motion was observed in which the number of rotating molecules depended on temperature. In the liquid phase both rotational and translational motions were observed. The latter corresponds to a jump, of the molecule, which was the in-plane lattice vector of the graphite layer. The translational diffusion constant showed a critical behavior.

Two-Dimensional Molecular Diffusion and Phase Transitions in HNO3-Intercalated Graphite Studied by Quasielastic Neutron Scattering. Batallan, F., Rosenman, I., Magerl, A., Fuzellier, H.: Physical Review B, 1985, 32[7], 4810-3