The structure of ultrathin Cu-phthalocyanine (Cu-Pc) film on Au(110) has been studied by means of several diffraction tecniques: helium atom scattering (HAS), low energy electron diffraction (LEED) and grazing incidence X-ray diffraction (GIXD). HAS has been used to measure the long range order of the organic overlayer, whereas LEED at 200 eV has been used to probe the corresponding substrate reconstruction. At the monolayer coverage, the Au(110) substrate displays a reconstruction with a 3-fold periodicity along the [001] direction, whose structure has been studied by out of plane GIXD and variable polarization X-ray absorption near edge spectroscopy (XANES). We found the structure of the substrate unit cell to be an asymmetric shallow (1 x 3) reconstruction with the Cu-Pc molecules tilted by an angle of similar to32degrees from the (110) surface plane.
