By analysis of the electronic contribution to the binding in A3C60, we show that the problem of orientational ordering can be mapped onto the fcc nearest-neighbor antiferromagnetic Ising model with J of the order of 100 K. The ground state crystal structure should be therefore antiferromagnetically ordered in two dimensions and disordered in the third. This is not inconsistent with present X-ray powder data. We find that the low-temperature conduction-band structure closely resembles that of the simplest antiferromagnetically ordered (so-called bi-directional) crystal. Calculated optical conductivity can be fitted by a Drude-like contribution and an "interband" Lorenzian peak at 400-500 cm-1.
 

Electronic Properties of Fullerenes. Proceedings of the International Winterschool on Electronic Properties of Novel Materials Editor(s): Kuzmany, H.; Fink, J.; Mehring, M.; Roth, S. Berlin, Germany: Springer-Verlag, 1993. p.211-18 of xiii+436 pp. 20 refs. Conference: Krichberg, Austria, 6-13 March 1993 ISBN: 3-540-57415-8.