The fullerene dimerization is considered as a consequence of donor-acceptor interaction between monomer molecules which is significant for C 60+C60 binary system. The dimerization is provided by a two-well structure of the ground state energy term. Analyzing characteristics of the term, proven by quantum-chemical calculations at different starting intermolecular distances, mechanisms of both physically (photoexcitation, thermal, high pressure, plasma, electron beam, and electric field) and chemically (alkali-metal adducts AC60) stimulated dimerization processes are suggested. © ;2007 Wiley Periodicals. Inc.