Adsorption site and orientation of pyridine on Cu{110} determined by photoelectron diffraction

The local adsorption geometry of pyridine on Cu{110} has been determined quantitatively using photoelectron diffraction in the scanned-energy mode. At high coverages the molecule adsorbs nearly atop a Cu atom in the close-packed rows with a N-Cu bond length of 2.00 Angstrom. Moreover, the Cu-N axis and the molecular (C-2) axis are inclined by 8 degrees and 20 degrees, respectively, to the surface normal. The result shows that not only the adsorption site of the emitter (in this case the N atom) but also the position of relatively light scatterers (the C atoms) can be determined by photoelectron diffraction. (C) 1999 American Institute of Physics. [S0021-9606(99)70119-4]