Sticking coefficients of CO,O2 and Xe on the (110) and (100) planes of tungsten

Sticking coefficients for oxygen, CO and Xe on the (110) and (100) planes of tungsten are presented as functions of absolute coverage, surface and gas temperature. Sticking coefficients for CO are in general higher and show simpler behavior than those for oxygen. Sticking coefficients for all gases studied are higher on (100) than on (110) under comparable conditions. It is concluded that simple Kisliuk models are applicable over much of the temperature range for CO on (110) and (100), but not for oxygen, where adsorption and reflection coefficients on first impact vary with coverage, and surface and gas temperatures in complicated fashion. For Xe, at low surface temperatures sticking coefficients are close to unity and increase with coverage, indicating better energy accomodation on Xe-covered than on clean tungsten.