Cj. Patton et al., IONIZATION IN COLLISIONS OF FAST H+ AND HE2+ IONS WITH FE AND CU ATOMS, Journal of physics. B, Atomic molecular and optical physics, 28(17), 1995, pp. 3889-3899
A crossed-beam technique, where the collision products have been selec
ted by time-of-flight (TOF) spectroscopy with either a pulsed beam or
coincidence counting, has been used to study pure ionization of Fe and
Cu by 70-1440 keV amu(-1) H+ and 35-425 keV amu(-1) He2+ ions. Cross
sections for the formation of q times ionized Fe and Cu products by pu
re ionization have been determined for q = 1-4. A comparison with the
corresponding (previously measured) cross sections for transfer ioniza
tion shows that, in the energy range considered, Fe+ and Cu+ ions aris
e predominantly through pure ionization. However, for q greater than o
r equal to 2 contributions from both transfer ionization and pure ioni
zation are important, Pure ionization becomes dominant at energies whi
ch increase as q increases. Measured cross sections for pure ionizatio
n have been successfully fitted to values based on an independent elec
tron model approximation.