Cluster ions ejected from an Li-Mg alloy liquid metal ion source: Observation of MG 2 (2+) and MG 3 (2+).

Ions ejected from a liquid metal ion source of an Li-Mg (10 atom %) alloy have been investigated by using a magnetic mass analyzer. In addition to singly charged homonuclear Li n (+) (n ≤ 9) and Mg n (+) (n ≤ 4) and heteronuclear MgmLi n (+) (m, n ≤ 2) clusters, doubly charged diatomic and triatomic Mg clusters are observed. Discussion is focused on the observability and the formation mechanism of the doubly charged small Mg clusters. A postionization process is suggested for the formation of the doubly charged clusters.