PHOTOINDUCED POLYMERIZATION OF SOLID C-70 FILMS

We report experimental evidence for the photopolymerization of C70 films under irradiation with visible or UV light. The tendency of C70 to dimerize is also confirmed by molecular dynamics calculations which find that the lowest energy dimer configuration contains a four-membered ring between monomers, similar to that calculated for the C60 dimer or 'bucky dumbell'. However, the cross section for this phototransformation is found to be considerably smaller than observed for C60, and this is attributed to a reduction in the number of reactive double bonds from 30 in C60 to only 5 in each polar cap of a C70 molecule.