Theoretical study of Aunclusters (n=1-5) deposited on a rutileTiO2(110) slab, concerning structure and stability

The initial nucleation of gold clusters Au-n(n= 1-5) on TiO(2)rutile (110) reduced surface is studied using density functional theory and a full-potential augmented-plane-wave method implemented in the WIEN2k code. The first two gold atoms remained tied to the surface with a bond length similar to those belonging to other well-known related materials, while the other gold atoms do not spread over the surface; they preferred to form a new layer. The occurrence of relativistic effects produced a preferential triangle geometry for Au(3)and a combination of triangular units for Au(4)and Au-5. The Au-Au average distance increased fromn= 2 ton= 5, indicating an expansion with a tendency to the bond distance found in the bulk. We are reporting an early 2D -> 3D transition of small folding, from Au-3 -> Au-4, followed by an Au-4 -> Au(5)transition of evident 3D character.