Low energy electron diffraction structure determination of the Ni(1 1 0)c(2×2)–CN surface phase

The structure of the Ni(1 1 0)c(2×2)–CN surface phase has been determined by quantitative low energy electron diffraction (LEED). Contrary to earlier suggestions that relatively intense fractional order LEED beams imply that adsorbate-induced Ni surface reconstruction occurs, the results confirm previous findings by scanned-energy mode photoelectron diffraction and medium energy ion scattering that no significant reconstruction occurs. The C–N axis is oriented along an open-packed 〈1 0 0〉 azimuth, with the molecule lying above a second layer Ni atom; the intramolecular axis is tilted by 23.7±4.5° relative to the surface plane. The adsorption does lead to a substantial (9±4%) outward relaxation of the outermost Ni layer spacing and small distortions of the outermost layers of the Ni substrate.