Incoherent quasi-elastic neutron scattering was used to study the behavior of the diffusion constant and molecular movements in the second stage of nitric acid intercalated into graphite near to the melting transition. The transition was continuous and the high-temperature phase was a lattice-liquid. The diffusion constant follows the critical behavior predicted in a defect mediated phase transition. However, the X-ray diffraction pattern was closer to that of a lattice liquid than that of a hexatic phase.

Critical Behavior of the Diffusion Constant in the Melting of the Layer of Nitric Acid Intercalated in Graphite. Batallan, F., Rosenman, I., Simon, C., Magerl, A.: Synthetic Metals, 1988, 23[1-4], 49-53