Optical spectroscopy of surfaces: Reflectance studies of chemisorption

摘要: A high precision technique has been used to study the small changes in near-normal incidence reflectance R caused by chemisorption of gases on an atomically clean metal surface maintained ultrahigh vacuum. Examples are given for O2, CO, and H2 Mo(100) photon energy range 1.9 <ℏω < 4.8eV. The relative change ΔRR is negative reaches as much 1%. Structure that appears ΔR(e), where e=exposure (pressure × time), attributed different binding configurations adatoms observed, e.g., LEED experiments. dependence ℏω suggests presence adsorbate-induced states within a few eV Fermi energy. Possible approaches determining dielectric function region from data discussed.