Atomic structure of monolayer graphite formed on Ni(111)

The atomic structure of monolayer graphite formed on a Ni(lll) surface was investigated by means of LEED intensity analysis. We measured the I-V curves of the (1,0), (0,1) and (1,1) diffraction spots from a (1 x 1) atomic structure, and analyzed them using Van Hove's analytical program based on dynamical theory. Three different atomic structures meeting the experimental requirement of the 3m symmetry were evaluated with Pendry's reliability factor. The final best-fit structure characterized by the minimum Pendry's reliability factor of 0.22 is as follows: one carbon atom in a unit cell of the graphite overlayer is located at the on-top site of the topmost Ni atoms, while another carbon atom exists at the fee hollow site. The spacing between the flat overlayer and the topmost Ni layer is 2.11 +/- 0.07 Angstrom, which is much narrower than the interlayer spacing in bulk graphite (3.35 Angstrom). (C) 1997 Elsevier Science B.V.