We present ab initio calculations for the intermolecular potential of C-60
in the low-temperature Pa (3) over bar structure as function of both the ro
tation angle and the lattice constant. These investigations are based on de
nsity-functional total-energy studies in the framework of the local-density
approximation (LDA). The zero pressure ground-state phase, selected Raman
frequencies, and the equation of state are determined in agreement with exp
erimental data. These results show that despite their well-known deficienci
es, LDA calculations are able to properly describe the angular and distance
dependence of the intermolecular potential for C-60 thus emphasizing the i
mportance of short-range chemical bonding in the Pa (3) over bar phase.