A HIGH-RESOLUTION NEUTRON-DIFFRACTION STUDY OF THE STRUCTURE OF AMORPHOUS HYDROGENATED CARBON, A-CH

Current structural models for amorphous hydrogenated carbon (a-C:H) ar e called into question on the basis of neutron-diffraction experimenta l work carried out al the ISIS pulsed neutron source (UK) on a-C:H. Th e nature of the neutron source allows the collection of data over an e xceptionally wide dynamic range that ensures a real-space resolution s ufficient to allow direct observation, for the first time, of contribu tions from the principal C-C bond types. The data also reveal details of the C-H correlations, and the presence of trapped molecular hydroge n.