STRUCTURE DETERMINATION FOR COADSORBED MOLECULAR FRAGMENTS USING CHEMICAL-SHIFT PHOTOELECTRON DIFFRACTION

Chemical shift photoelectron diffraction has been applied to the model system of coadsorbed PFx(x=1,2,3) species on Ni(111), produced by ele ctron beam fragmentation of a PF3 overlayer, to determine quantitative ly and independently the local adsorption site of each species. PF3 is found to occupy atop adsorption sites above the outermost Ni layer at oms at a P-Ni bond length of (2.07 +/- 0.05) angstrom, PF2 occupies br idge sites at a spacing of (1.70 +/- 0.05) angstrom, while the PF spec ies occupy both types of threefold coordinated hollow sites, maintaini ng a constant P coordination throughout the fragmentation.