The rehybridization of CO with K coadsorption on Ru(001)

The recently observed ‘‘rehybridized’’ CO, produced by coadsorption with (1)/(3) monolayer of potassium on Ru(001), is studied by cluster calculations. The photoemission and Auger spectroscopic results are consistent with the effects produced by the strong electric field in an ionic K–CO local complex in which the σ orbitals are indeed rehybridized and the 1π level is split. The experiments are not consistent with an sp² hybridized >C–O species or a (CO)²⁻₂ potassium salt. A long‐range electric field arising from hypothetically positive potassium also produces electronic changes in the wrong direction to explain the spectra.