The Au/Ti(0 0 0 1) adsorption system was studied by low energy electron diffraction (LEED) and photoemission spectroscopy with synchrotron radiation after step-wise An evaporation onto the Ti(0 0 0 1) surface. For adsorption of Au at 300 K, no additional superstructures were observed and the (I x 1) pattern of the clean surface simply became diffuse. Annealing of gold layers more than I NIL thick resulted in the formation of an ordered Au-Ti surface alloy. Depending on the temperature and annealing time, three surface reconstructions were observed by LEED: (root 3 x root 3) R30 degrees, (2 x 2) and a one-dimensional incommensurate (root 3 x root 3) rectangular pattern. The An 4f core level and valence band photoemission spectra provided evidence of a strong chemical interaction between gold and titanium. The data indicated formation of an intermetallic interface and associated valence orbital hybridization, together with diffusion of gold into the bulk. An core-level shifts were found to be dependent on the surface alloy stoichiometry. (c) 2006 Elsevier B.V. All rights reserved.