Electronically mediated sputtering in thin gold films, bombarded with 200-M
eV Ag ions, has been observed by ex-situ thickness measurements of the film
using x-ray reflectivity technique. The observed sputter yield depends upo
n the film thickness and is about 410 atoms per incident ion for films of t
hickness 150 Angstrom and 235 atoms per incident ion in 450-Angstrom -thick
film. This sputtering rate is a few orders of magnitude higher as compared
to that normally encountered in the regime of elastic collisions. Reduced
mobility of the electrons due to scattering from the surface and the grain
boundaries plays an important role in enhancing the effects of electronic e
xcitations. Sputtering is accompanied by a significant smoothening of the f
ilm surface and smearing of the boundaries between the grains.