Abstract A typical keV-ion loses a considerable part of its energy through excitation and ionization of the target electronic system. In alkali halides this energy can be efficiently used for dissociation of the irradiated material which can subsequently desorb in the form of atoms or molecules. In order to study these processes we have measured yields and time of flight spectra of ejected neutrals as well as the intensity of the optical radiation emitted from the sputtered atoms. By comparison of electron- and ion-induced data we were able to determine the contribution of the electronic mechanism in low energy sputtering. The results are described by a simple model in which stoichiometry changes at the bombarded surface set limits to various sputtering and desorption processes.