The benzene/graphite diffusion is highly interesting as a model system for diffusion of physisorbed molecules in general and for the understanding of lubrication in carbon systems in particular. Previous neutron spin-echo (NSE) and helium spin-echo (HeSE) measurements of sub-monolayer films of benzene on graphite have shown a continuous or Brownian (group) diffusion behaviour, with the system giving unique information about the laws that rule the energy exchange between adsorbed molecules and surfaces at the nanoscale. The published data, however, rely on coherent scattering and a limited (high resolution) spectral range. From incoherent backscattering measurements we have strong indication that important additional information (rotation/translation) can be obtained with incoherent scattering in the micro- to millielectronvolt range. These measurements are the aim of this proposal.