REACTION OF SICN-6) AND SICN- (N=2-4) WITH O-2 MOLECULES IN A RADIO-FREQUENCY ION-TRAP( (N=1)

Ion-molecule reactions of silicon-carbon binary cluster ions SiCn+ (n= 1-6) and SiCn- (n=2-4) with O-2 molecules were studied by using an rf ion trap. For all selected positive and negative parent ions, only SiC nO+ or SiCnO- were produced, respectively. The rate constants for the oxidation of these clusters were determined for the first time. The si ze dependence of the reactivities are discussed, and the presence of t he ring form positive ions for n=3 and 5 are suggested. (C) 1995 Ameri can Institute of Physics.