Structure determination for coadsorbed molecular fragments using chemical shift photoelectron diffraction

Chemical shift photoelectron diffraction has been applied to the model system of coadsorbed ${\mathrm{PF}}_{\mathit{x}}$(x=1,2,3) species on Ni(111), produced by electron beam fragmentation of a ${\mathrm{PF}}_3$ overlayer, to determine quantitatively and independently the local adsorption site of each species. ${\mathrm{PF}}_3$ is found to occupy atop adsorption sites above the outermost Ni layer atoms at a P-Ni bond length of (2.07±0.05) Å, ${\mathrm{PF}}_2$ occupies bridge sites at a spacing of (1.70±0.05) Å, while the PF species occupy both types of threefold coordinated hollow sites, maintaining a constant P coordination throughout the fragmentation.