COMPTON PROFILES AND ELECTRONIC DENSITY IN C-60

High-resolution measurements of Compton profile on C-60 powder have be en carried out as a function of temperature both below and above the o rientational ordering phase transition (260 K). Simultaneously, theore tical profiles are obtained using the plane-wave expansion of wave fun ctions from an ab initio self-consistent field calculation (SCF) of th e energy band structure, using the linear combination of atomic orbita ls (LCAO) method within the local-density approximation. Compared to g raphite, the C-60 profiles indicate substantially greater delocalisati on of the ground-state charge density. We have demonstrated, both by e xperiment and calculation, that this delocalisation is mainly a molecu lar effect.