Chemisorption and dissociation of O 2 on Cr(110): An EELS/ESDIAD study

Abstract

Electron stimulated desorption ion angular distributions (ESDIAD) and high resolution electron energy loss spectroscopy (EELS) have been used in conjunction with Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) to identify molecular and atomic binding states for oxygen chemisorbed on Cr(110). Dissociative chemisorption occurs at and above 120 K, although below 200 K an additional minority molecular binding state is simultaneously populated. A six-fold symmetric ESDIAD pattern for the molecular state and an O 2 vibrational frequency of 1020 cm −1 are suggestive ofsuper-oxy O 2(ads) bonding to Cr(110) at six equivalent local sites.