IS A 1.90 ANGSTROM C-C BOND-LENGTH IN POLYMERIC FULLERIDES POSSIBLE

The very long C-C intrafullerene bond distance of r(long) = 1.90(15) A ngstrom in RbC60 polymeric fulleride observed by Stephens et al. is un precedented. Large scale full geometry optimizations using non-local d ensity functional theory on C-120, C-120(2-), C-120(6-), as well as on the model dinaphthalene dimer were performed in exploring the potenti al energy surface along the long C-C bond in question. For neutral C-1 20, r(long) should be close to 1.61 Angstrom, a value that is in agree ment with the experimental value for the C-12O buckyball dimer and is close to the lower limit of the Stephens C-C value. (C) 1998 Elsevier Science B.V.