Ab initio all-electron calculations for carbon and oxygen chemisorbed on nickel clusters indicated that the charge redistribution induced by the adsorbate causes repulsive stresses between the metal surface atoms. Using lattice-dynamics calculations, it was shown that these stresses could account for the observed S4-phonon anomaly with c(2 x 2) oxygen overlayers, and also explain the carbon-induced surface reconstruction, via a softening of the A2 mode at x The reconstruction was also reproduced directly by total-energy calculations with use of a suitable cluster.

Adsorbate-Induced Surface Stress - Phonon Anomaly and Reconstruction on Ni(001) Surfaces. J.E.Müller, M.Wuttig, H.Ibach: Physical Review Letters, 1986, 56, 1583-6