Phonon dispersion of the (22) phase of carbon on the reconstructed Ni(100) surface

The phonon spectrum of the (2×{}2) phase of carbon corresponding to a saturation coverage of half a monolayer on the reconstructed Ni(100) surface has been investigated along the {Γ}{}-X{} direction by electron-energy-loss spectroscopy. Both the dispersion of the adsorbate modes and of various surface resonances and surface phonons are measured along the [110] direction. The experimental data are compared with the results of a lattice-dynamical model calculation with the nickel atoms in the displaced equilibrium positions of the reconstructed surface.