IONIC CHARGE DEPENDENCE OF THE ZERO DEGREE BINARY ENCOUNTER PEAK FOR PARTIALLY STRIPPED HEAVY-IONS

We report on the measurements of double differential cross sections, a t zero degree, for the production of secondary electrons from the coll ision of 0.6 MeV amu(-1) Cu5+, I7+, Au11+, U13+, Cu19+, I23+ and Au29 projectiles with H-2 and He. The shapes ad positions of the observed binary encounter electron peaks are compared with continuum distorted wave-eikonal initial state (CDW-EIS), impulse approximation and classi cal trajectory Monte Carlo calculations, as well as with predictions F rom an adiabatic resonant tunnelling model recently proposed by Fainst ein and co-workers. The experimentally observed binary peak positions were found to be essentially determined by the projectile's ionic char ge q and to be independent of the projectile's nuclear charge Z(P). Al though the experimental conditions correspond to the strong perturbati on regime, i.e. 1.0 less than or equal to q/V-P less than or equal to 5.9 (V-P being the projectile velocity), the CDW-EIS approach accounts well for the position and shape of the binary peak.