ON THE SPECTRAL LINESHAPES, LIFETIMES AND DEEXCITATION PROCESSES OF AUTOIONIZING STATES PRODUCED IN INELASTIC ION-SURFACE COLLISIONS

The natural lineshapes of peaks in electron spectra due to decay of au toionizing states of Ne, formed in collisions of Ne with Mg and Al sol id targets, are modelled. The modelling takes into account the level s hifts of the excited and ionic states of the atom in front of the surf ace and various resonant and Auger capture and loss processes. It is s hown that rather complex lineshapes may be expected. The electron spec trum will generally possess a peak at energies in the vicinity of that corresponding to autoionization of a free atom, as well as a high-ene rgy tail and secondary maximum. It is suggested that a structure obser ved at 22.2 eV in the experimental Ne* electron spectrum is just such a secondary maximum associated with the decay of the Ne* P-3 3s(2) n ear the metal surface. The effects of varying the model lifetimes, ele ctron capture and deexcitation rates are discussed.