Sequential precursors in dissociative chemisorption: O2 on Pt(111)

A physisorbed state for O2 on Pt(111) has been identified by XPS spectroscopy and demonstrated to be an intrinsic precursor to molecular chemisorption. Combined with the prior demonstration that the molecularly chemisorbed species is a precursor to dissociation, we propose a model of sequential precursors to describe dissociation. © 1989 The American Physical Society.