Atomic vibrations in carbon fibres

Longitudinal lattice vibrations with wavelengths between 7 and 30 Å have been observed along the crystallographic c-axis in carbon fibres by the method of neutron spectrometry. The vibrations propagate for at least 150Å and have frequencies 15 per cent less than those found in pyrolytic graphite. Measurements of the 0002 Bragg peak indicate crystal sizes along the c-axis of order 200Å with a lattice spacing 6.82 ± 0.02Å. This can be compared …