Structural studies of multiwall carbon nanotubes by neutron diffraction

We report on structural studies of multiwall carbon nanotubes by wide-angle neutron scattering up to a maximum scattering vector Q(max) = 166 nm(-1). The derived reduced radial distribution functions of the nanotubes are comp ared to those determined for graphite and turbostratic carbon, providing ev idence that the stacking pattern of graphene tubules in multiwall carbon na notubes is intermediate between those of the other two carbon forms. The (0 02) and (004) peaks of the nanotubes appear at smaller angles than graphite , yielding the intertubule spacing of 0.341 nm. At small length scales (les s than or similar to 0.5 nm) the nanotube structure resembles that of graph ite, including graphitelike interlayer correlations for at least a few adja cent layers. Beyond this range, a systematic decrease in peak amplitudes an d deviation from the graphite structure is observed. [S0163-1829(99)06903-9 ].