The effect of Li deposition on the sputtering of Si+ from oxygenated Si surfaces has been studied. It is observed that at low oxygen coverages, the Si+ yield decreases exponentially with the Li induced decrease of the work function ϕ. With the formation of thermally grown silicon oxide on the surface, the Si+ yield deviates from the simple exponential dependence on ϕ. The Si+ yield becomes independent of ϕ for an appreciable range of ϕ in cases of heavier oxidation. © 1983 IOP Publishing Ltd.