Collision-induced dissociation of Co+n (n=2–18) with Xe: Bond energies of cationic and neutral cobalt clusters, dissociation pathways, and structures

Abstract

The kinetic energy dependence of collision-induced dissociation (CID) of Co+n (n=2–18) with xenon is studied by using a guided ion beam mass spectrometer. Examination of the general dissociation behavior over a broad collision energy range shows that cobalt cluster cations dissociate exclusively by loss of single atoms (cluster ‘‘evaporation’’), with no evidence found for elimination of molecular cluster fragments. Bond dissociation energies for cobalt cluster cations, Co+n (n=2–18), are determined from measurements of the CID thresholds. Bond energies for neutral cobalt clusters, Con (n=4–18), are derived by combining these cationic bond energies with ionization energies for Con from the literature. The dependence of binding energy on cluster size is similar to that observed for iron clusters, and inspires some speculation regarding cluster ion structures.