Production of Fe clusters by collisions of metal vapour with supersonic argon beams

Abstract

Abstract. The growth of Fe clusters by collisions of Fe atoms with Ar atoms flowing in a supersonic beam was investigated by Fe mass flux measurements and transmission electron (TEM) microscopy. Moderate Ar densities of the order of 1×10 20 m −3 were sufficient to cause cluster growth which was attributed to the low temperature of the Ar beam. TEM imaging of deposited clusters revealed diameter distributions from 2 to 10 nm depending on the deposition time. Extrapolation to zero deposition time revealed a cluster size of 2.4 nm grown in the gas phase. Growth on the surface was attributed to diffusion of single Fe atoms which are co-deposited with the clusters in the process and which agglomerate when they hit a cluster.

An intense source for cold cluster ions of a specific composition

“…Owing to these features, metal clusters are in the focus of material science and a number of different production techniques have emerged from this research activity. 12,13 In order to perform reasonably insightful experiments into how the properties of matter develop with the number of constituents, these production techniques must provide sufficient control of size. Experiments with mass-selected clusters are of paramount importance in this context.…”