Dissociation mechanisms of cluster ions resolved using ab-initio molecular orbital calculations

2007

We have examined the cluster-size effect on fragments in the collision-induced dissociation (CID) of small boron clusters (B + n , n ≤ 8) by means of ab-initio molecular orbital (MO) calculation, for conditions representative of low-Z cationic clusters in plasma. Single cations B + (leaving B 0 n-1 ) are predominantly fragmented from small clusters B + n (n < 5) by low-energy collisions (<10 eV) with Xe atoms. With increasing the size n, beyond n = 5, B + n-1 (leaving B°) clusters are observed preferentially. This alternating trend in experiment has not been quantitatively explained by previous ab-initio MO calculations. We used a density functional method called B3LYP and basis functions 6…