Initial-state shift of the carbon 2s levels of chemisorbed hydrocarbons on nickel

uv photoemission results using filtered hν=40.8-eV radiation show strong shifts in the low-lying C(2s)-derived levels of chemisorbed hydrocarbons on Ni relative to the higher-lying σ levels. These differential shifts provide evidence for initial-state potential and/or rehybridization effects which are important in interpreting high-lying valence orbital shifts and the bonding of chemisorbed species. © 1978 The American Physical Society.