Melting of alloy clusters: effects of aluminum doping on gallium cluster melting.
Calorimetry measurements have been performed as a function of temperature for size-selected Ga(n-1)Al+ clusters with n = 17, 19, 20, 30-33, 43, 46, and 47. Heat capacities determined from these measurements are compared with previous results for pure Ga(n)+ clusters. Melting transitions are identified from peaks in the heat capacities. Substituting an aluminum atom appears to have only a small effect on the melting behavior. For clusters that show melting transitions, the melting temperatures and latent heats for the Ga(n-1)Al+ clusters are similar to those for the Ga(n)+ analogs. For Ga(n)+ clusters that do not show first-order melting transitions (n = 17, 19, and 30) the Ga(n-1)Al+ analogs also lack peaks in their heat capacities. The results suggest that the aluminum atom is not localized to a specific site in the solid-like Ga(n-1)Al+ clusters.
Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA.
Colleen M
CM
Neal
Anne K
AK
Starace
Martin F
MF
Jarrold