The fragmentation of SF6 under O− and Al− negative ion impact

Abstract

The fragmentation of SF6 under 15–30 keV O− and 20–30 keV Al− impact has been studied using a crossed beam technique. The recoil ions and ion pairs are identified in coincidence with scattered projectiles with different charge states by the usage of time-of-flight (TOF) mass spectroscopy. The yield ratios of fragment ions to [Formula: see text] and the yield ratios of ion pairs to (S+, F+) in collision with O− and Al− are obtained and compared with those of H− and C−. It is found that the ratios have a very strong dependence on the momenta of the projectiles. Besides, by analyzing the TOF spectra, it is also found that more [Formula: see text] with n odd are produced than those with n even under O−, Al− impact, which also happened in collision with H− and C−, positive ion and electron impact. The dissociation channels of [Formula: see text] are found to be insensitive to incident ions’ energy and kind in our energy range.