Structure and lattice dynamics of K1C60 in the orthorhombic phase: a neutron scattering study

Rietveld refinement of neutron diffraction from a powder sample of K1C60 in the orthorhombic phase using a model having polymeric linking by [2+2] cycloaddition of the C60 molecules yields physically reasonable bond lengths from 1.44 to 1.54 إ between C atoms in the vicinity of the link. Neutron time-of-flight inelastic scattering measurements display a band of vibrations consistent with linking between 10 and 25 meV not present in pure C60 or in the fcc phase of K1C60. Diffuse scattering is accounted for in terms of rotationally disordered C60 in minority phases and in unlinked boundary regions between polymer grains.