Investigation of electronic density in C-60 by Compton scattering

High-resolution measurements of Compton profiles on C-60 as well as KxC60 have been carried out using 16 keV photons at LURE (Orsay, France) and at ESRF (Grenoble, France). Theoretical profiles are obtained using the plane wave expansion of wave functions from an ab-initio self-consistent field calculation of the energy band-structure. The linear combination of atomic orbitals method within the local-density-approximation has been employed for the calculation. In all cases, the agreement between theory and experiment is excellent. The C-60 profiles indicate substantially greater delocalization of the ground-state charge density, compared to graphite. We have demonstrated, both by experiment and calculation, that the delocalization in C-60 is mainly a molecular effect.