MECHANISMS OF METASTABLE N-2 AND KR ELECTRON-STIMULATED DESORPTION FROM N-2-KR DOUBLE-LAYER AND MIXED FILMS

Desorption of metastable particles from layered and mixed films, compo sed of N-2 and Kr, is induced by the impact of 6-50 eV monoenergetic e lectrons. From yield functions and time-of-flight analysis of the meta stable particles emanating from these films, N-2 and Kr* are identifi ed as the desorbing species. Basic mechanisms responsible for their de sorption are discussed. It is suggested that the desorption of Kr ari ses from dissociation of transitory [Kr-N-2] excimers. The desorption of N-2 can arise from cavity expulsion, intramolecular vibrational e nergy transfer (with or without prior electronic excitation energy tra nsfer from Kr excitons to N-2) and the dissociation of [Kr-N-2] excim ers. (C) 1997 Elsevier Science B.V.