Unusual state of adsorbed CO: CO(√3 × √3 )R30°/Cr2O3(111)

Abstract
A new form of CO is found for adsorption on an oxide surface, where an ordered array of CO is found by angle-resolved photoemission to be bound in a tilted or lying-down mode. This new bonding configuration has very strange features which are discussed, including strange ordering of valence bands and abnormal binding energies. A simple model is presented.