Coalescence reactions in (C-70)(m)Ir-x clusters

A mass spectrometric investigation of the photofragmentation behavior of mi xed clusters composed of C-70 molecules and iridium atoms (C-70)(m)Ir-x (m= 2, 3; x >2) reveals that coalesced fullerenes C138-2n and C206-2n (n=0, 1, 2,...) are the predominant reaction products at high laser intensities. Mor e detailed tandem time-of-flight experiments on mass selected (C-70)(2)Ir-x indicate that the efficiency of the coalescence reaction increases with in creasing iridium content in the precursor cluster. Most probably the format ion of strongly bound IrC molecules plays an important role for the reactio n mechanism. For comparison, the fragmentation behavior of preselected (C-7 0)(2)Co-5 is also investigated. (C) 2001 American Institute of Physics.