Electronic sputtering of solid nitrogen and oxygen by keV electrons

Sputtering of solid N₂ and O₂ has been performed with electrons in the keV regime by means of a quartz microbalance technique. Good agreement is found between the sputtering yields obtained with this and the emissivity-change method. O₂ sputters more efficiently than N₂, although these solids are very similar in their physical properties. The yields are almost proportional to the electronic stopping power of the primary electrons. Different models for electronic sputtering of solid condensed gases are discussed and compared with the results. For low excitation densities predictions are attempted on the basis of a simple collision-cascade model where the low-energy cascades are generated by kinetic energy release from electronic deexcitations.