STABILITY OF CLUSTERS OF FULLERENES

We have studied the formation and stability of pure and mixed clusters of C-60 and C-60/C-70 produced in a gas aggregation source. The sourc e yields very smooth abundance distributions indicating an efficient c ooling. The stability of the clusters was probed by varying the degree of heating with a XeCl excimer laser (hv < I.P.) followed by single p hoton ionisation with a F-2 excimer laser. The stability patterns show features related to geometrical packing structures but much stronger than previously seen in cluster spectra. The fragmentation patterns fo r the mixed clusters indicate that C-60 and C-70 have similar binding energies in the clusters in contrast to what would be expected from va pour pressure data of macroscopic samples.