Mass spectroscopic study of metal-rich nanoclusters

Metal-rich K 1 - 5 ( KI ) n + (n ∼27) clusters were produced by the supersonic cooling expansion of laser-induced KI plasma. The obtained mass spectroscopic peaks show the unique magic numbers at n = 9, 13, and 22 for K1(KI)n; n = 8, 12, and 21 for K2(KI)n; n = 8, 12, 16, and 21 for K3(KI)n; n = 7, 9, 11, and 13 for K4(KI)n; and n = 12 and 21 for K5(KI)n. These magic numbers are fairly different from those of other reported metal-rich Na 1 - 9 ( NaF ) n + and Cs 1 - 5 ( CsI ) n + clusters. It is interesting to note that K 2 , 3 , 5 ( KI ) n + clusters have the same magic numbers at n = 12 and 21 and possess structures that are closely related to the 3 × 3 × 3 and 3 × 3 × 5 cubic structures with the excess electron at the side anion vacancy or the center anion vacancy.