Data are presented which yield relative magnitudes of the initial, room‐temperature sticking probabilitiesS0of nitrogen on clean tungsten and oxygen on clean silicon and germanium. TakingS0to be 0.35 for N2on W, we obtain 1×10−2and 8×10−4forS0of O2on Si and Ge, respectively. Data are also given concerning the temperatures at which the atomically clean surface is thermally regenerated from the oxygenated surface for both Si and Ge.