σ -bonding contribution of a strong π -acceptor molecule : Surface chemical bond of SO2 on Ni(100)
We study the electronic structure and chemical bonding of the SO2 molecule adsorbed on Ni(100) surface using x-ray emission spectroscopy at the O1s absorption edge. Elemental and symmetry specificities of the method enable us to directly probe surface chemical bonding formed by strong hybridization of O2p with Ni3d orbital. Contrary to the expected π bonding due to strong π acceptor character of t