SURFACE-IONIZATION MECHANISM OF ALKALI-HALIDES

Surface ionization is one method for generating a quiescent plasma, wh ose apparatus is well-known as a Q-machine. The mechanism, however was not well known except for alkali metals. To examine the previously pr oposed generalized surface ionization model, the ionizations of NaCl a nd NaBr have been experimentally studied by using a mass spectrometer equipped with a thermal ion source. The results clearly show that the ionization at lower temperatures is governed by the 'dissociative ioni zation (DI)' process and one at higher temperatures is governed by the 'neutral dissociation and ionization (NDI)' process. Copyright (C) 19 96 Elsevier Science Ltd.