BINDING OF DEUTERIUM TO ICOSAHEDRAL NICKEL AND COBALT CLUSTERS

The binding of deuterium atoms to icosahedral nickel and cobalt cluste rs in the 55 to 147 atom size region is studied at near room temperatu re conditions. The icosahedral clusters have closed shells at 55 and 1 47 atoms and closed subshells at many intermediate sizes. Deuterium sa turation levels are determined for many of the closed shell and subshe ll clusters in this size region. From the series of saturation levels a set of binding rules (appropriate to room temperature conditions) ha ve been determined that allow a prediction of the observed coverages f or the entire series of closed shell and subshell clusters. The config urations of D-atom binding sites for clusters containing 55, 71, 83, 9 2, 101, 116, and 147 atoms are given, In general, the ratio of D atoms to surface metal atoms is near unity.