Structure of a-C:H(D) by neutron diffraction and isotopic enrichment

Three samples of amorphous hydrogenated carbon with varying degrees of isotopic enrichment have been studied using neutron diffraction. By using these samples in three independent diffraction experiments it has been possible to derive the partial pair correlation functions associated with the distinct C:C C:H and H:H correlations. The isotopic substitution method within neutron diffraction has thus afforded a view of unique clarity of the atomic-scale structure of this complex family of materials. The data are discussed within the context of current structural models, and in the light of complementary data from inelastic neutron scattering and MAS/NMR.