Modification on the melting of aluminum nanoclusters by a copper atom: heat capacities of CuAl$_{n-1}^{-}$ nanoalloys

The melting of alloyclusters is currently of great interest and emerging as an important research area. In this talk, we report the synthesis and melting transition of CuAl$_{n-1}^{-}$ nanoalloy clusters (n = 49 -- 62). Heat capacities and melting behaviors have been determined for CuAl$_{n-1}^{-}$ nanoalloy clusters using a novel collision induced dissociation method and are compared with those of pure aluminum cluster Al$_{n}^{+}$. All these nanoalloys present a first order melting transition at temperatures well-below the melting temperature of the bulk aluminum and the eutectic temperature of their bulk alloys. No eutectic characteristic is detected for these nanoalloyclusters. Upon substitution of Al with a single copper atom, the melting of pure aluminum clusters has been altered considerably. Size and charge effects of the doping atom on the melting of host nanoclusters are discussed.