COLLISIONAL FRAGMENTATION OF AR-AT-C-60

The fragmentation patterns resulting from collisions between (Ar@C-60) (+) or (Ar@C-60)(-) ions and H-2, He, CH4, Ne, Ar and Kr target gases have been measured. The ion-source material Ar@C-60 was synthesized by healing C-60 under 3000 atm of argon gas, leading to a 10(-3) concent ration of endohedral fullerenes. The fragmentation spectra (charged mo lecules only) are dominated by positive ions both when positive or neg ative endohedrals break up. Endohedral fragment ions Ar@C-n(+) (48 les s than or equal to n less than or equal to 60) as well as all carbon f ragments are observed. For collisions involving (Ar@C-60)(-), ejection of the Ar atom together with two electrons, without permanently damag ing the fullerene cape, is a prominent reaction channel, indicating th at a 'window' or a deformation in the form of e.g. a large hole throug h which the argon atoms can exit, is opened during the collision. (C) 1998 Elsevier Science B.V.