The projectile charge state dependence of binary encounter electron (BEe) production was studied at zero degrees with respect to the beam direction for collisions of 19 and 28.5 MeV F(3-9)+ with Hz and He targets. The measured double differential cross sections for BEe production were found to be increasingly enhanced with decreasing projectile charge state contrary to the usual screening behaviour. The relative enhancement of the BEe F8+ yields over the F9+ yields was found to be about 15% increasing to about 50% for F3+ projectiles. Plausible mechanisms are discussed; however, no theoretical explanation of this anomalous enhancement is established.
Doubly differential cross sections d2v/dEE dCl. and fractional probabilities for binary encounter (BE) electron emission at 0" electron emission angle as a function of initial ( 4 , ) and final (4,) projectile charge state have been measured for 0.53 MeV"-' F' , on H,. The data confirm the surprising decrease of the panial cross section with increasing charge state of the incoming projectile q, reponed by Richard el al. We show by coincident electron projectile detection that the pure ionization channel q, = q, strongly dominates the differential cross section at 8.=0' and projectile capture and loss channels are of negligible imponance.In view of a recent calculation by Olson el 01 we conclude from our data that 0' BE electron emission depends strongly on the shape of the screened projectile potential varying with qi.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.