Thermal metal cluster anion reactions: behavior of aluminum clusters with oxygen

Aluminum anions, (Al−n,n=5–>40), were generated using laser vaporization and equilibrated to room temperature in a flow tube apparatus. The behavior of these species, in general, show a propensity to lose the neutral oxides. In sharp contrast, several anions, Al−13, Al−23, and Al−37, show special inertness to these etching reactions and indeed, the etching reactions even contribute to their further production. The jellium model predicts these species to have closed shells. There are some exceptions in reactivity, however, which indicate the likelihood that the local structure may also play a role. An odd/even alternation, where even atom clusters react more quickly than successive odd ones, is also apparent. This is attributed to electron pairing within the cluster.