High resolution x-ray emission spectroscopy is shown to reveal unprecedented details of the chemical bond formed between a molecule and a transition metal surface. An atom and symmetry projected view of the bonding orbitals is obtained. We find that all outer and inner valence orbitals of the molecule change due to the surface interaction. New types of molecular states are observed which are a direct signature of the surface chemical bond.

• Received 24 July 1996

DOI:https://doi.org/10.1103/PhysRevLett.78.2847