Ionization and charge transfer in collisions of highly charged ions with helium at low velocity

Abstract

Ionization and charge transfer in slow collisions between highly charged projectiles and helium atoms are studied by the two-center atomic orbital close-coupling method within the independent electron approximation. The relative importance of single ionization to single capture is investigated. Our calculations show that ionization cross sections for ${\mathrm{C}}^{6+}$, ${\mathrm{N}}^{7+}$, and ${\mathrm{O}}^{8+}$ projectiles increase rapidly between v=1 and 2 a.u. The onset is dependent on projectile charge state. At a fixed velocity, ionization cross sections decrease with increasing projectile charge. It is also found that ionization and charge transfer occur at about the same impact parameter range.