Ultrahigh vacuum and high-pressure coadsorption of CO and H2 on Pd(111): A combined SFG, TDS, and LEED study

Abstract

Nonlinear optical sum frequency generation vibrational spectroscopy was applied together with TDS and LEED to study adsorbate-adsorbate interactions of CO and H2 on Pd(111) both under UHV and high-pressure (mbar) conditions. It was shown that the mutual site blocking of CO and H2 and thus, the resulting adsorbate structures strongly depended on the type of gas exposure and the exposure temperature.