A surface core-level shift photoemission study of the interaction of oxygen with W{100}

The interaction of oxygen with W(100) up to a coverage, θ, of ~ 2.2 monolayers has been studied using the surface W4f core-level photoemission shifts recorded using synchrotron radiation at a hν of 130 eV. Discreet chemical shifts ascribed to W bonded to overlayer oxygen; W in a 2d reconstructed oxide layer (formed by annealing above ~ 700 K); W in a WO2-like crystallite state; and W in overlayer oxygen saturated W(110) facets (heating at high coverage) have been observed. Simultaneous Auger and LEED data were used to support the assignments by comparison to the detailed previous work that exists in the literature for this system using LEED, Auger, Δφ, ESD and ISS techniques. © 1989.