Geometries, stabilities, and magnetic properties of AunTi (n = 1–9) clusters: A density functional study

The geometrical structures, relative stabilities, and magnetic properties of AunTi (n = 1–9) clusters have been studied by using density functional method PW91. An extensive structural search shows that the Ti atom in low-energy AunTi isomers tends to occupy the most highly coordinated position. The ground state structures of AunTi clusters are different from that of Aun+1 clusters. The relative stabilities of ground state AunTi clusters are analyzed based on the averaged binding energies, second-order difference of energies, and HOMO–LUMO energy gaps. It is found that the substitution of a Ti atom for an Au atom in gold cluster enhances the stability of the host cluster. The AunTi clusters with even n exhibit higher stability over the clusters with odd n. The chemical activity of AunTi clusters is higher for odd n and lower for even n than that of the corresponding Aun+1 clusters. The Au4Ti cluster, which corresponds to a large energy gap, has a large VIP. The magnetism calculations indicate that the magnetic moment of the Ti atom in the ground-state AunTi (n = 3–9) clusters is reduced to 0.75–1.15 μB for odd n and is completely quenched for even n.