RT info:eu-repo/semantics/article
T1 Substituting a copper atom modifies the melting of aluminum clusters
A1 Cao, Baopeng
A1 Starace, Anne K.
A1 Neal, Colleen M.
A1 Jarrold, Martin F.
A1 Nuñez, Sara
A1 López Rodríguez, José Manuel
A1 Aguado Rodríguez, Andrés
K1 Materiales magnéticos
AB Heat capacities have been measured for Al(n−1)Cu− clusters (n = 49–62) and compared with results for pure Aln+ clusters. Al(n−1)Cu− and Aln+ have the same number of atoms and the same number of valence electrons (excluding the copper d electrons). Both clusters show peaks in their heat capacities that can be attributed to melting transitions; however, substitution of an aluminum atom by a copper atom causes significant changes in the melting behavior. The sharp drop in the melting temperature that occurs between n = 55 and 56 for pure aluminum clusters does not occur for the Al(n−1)Cu− analogs. First-principles density-functional theory has been used to locate the global minimum energy structures of the doped clusters. The results show that the copper atom substitutes for an interior aluminum atom, preferably one with a local face-centered-cubic environment. Substitution does not substantially change the electronic or geometric structures of the host cluster unless there are several Aln+ isomers close to the ground state. The main structural effect is a contraction of the bond lengths around the copper impurity, which induces both a contraction of the whole cluster and a stress redistribution between the Al–Al bonds. The size dependence of the substitution energy is correlated with the change in the latent heat of melting on substitution.
PB American Institute of Physics
YR 2008
FD 2008
LK http://uvadoc.uva.es/handle/10324/2470
UL http://uvadoc.uva.es/handle/10324/2470
LA eng
NO J. Chem. Phys. 129, 124709 (2008)
NO Producción Científica
DS UVaDOC
RD 24-nov-2024