Room-temperature surface structure of 4-aminobenzoic acid on Cu(110) surfaces

The room-temperature adsorption of 4-aminobenzoic acid on a Cu(110) surface is studied with high-resolution electron energy-loss spectroscopy (HREELS) , low-energy electron diffraction (LEED), temperature-programmed desorption and scanning tunnelling microscopy. Initially, the molecule adsorbs in a f lat-lying geometry and forms domains with a periodicity of (3 x 4g). Increa sing the coverage, the surface is saturated with this flat-lying structure at a coverage of 0.167 ML. Further increasing the surface coverage, the HRE EL spectrum shows some additional upright species without any change in LEE D pattern. Scanning tunnelling microscopy shows that this upright species i s present along domain boundaries that are preferentially aligned along the (3, +/-4) directions. Copyright (C) 2001 John Wiley & Sons, Ltd.