Direct evidence for projectile electronic structure effects in slow multielectron capture collisions

Abstract

We investigate the role of the electronic structure of the projectile in ionization and subsequent fragmentation of CO${}_2$ induced by multielectron capture in collisions at 0.31 a.u. impact velocity. Focusing on the ${\text{CO}}_2^{3+}\to {\text{O}}^{+}:{\text{C}}^{+}:{\text{O}}^{+}$ break-up channel as a representative channel, we report kinetic energy release distributions (KERDs) for collisions with equi-velocity N${}^{q+}$ and O${}^{q+}$ projectiles. We consider two complementary categories of measurements. In the first category, in which different projectiles of the same charge are considered, we find that KERDs obtained with N${}^{q+}$ and O${}^{q+}$ impact ($q=4,6$) are broadly similar, but they differ significantly from the earlier reported KERD with Ar${}^{q+}$ impact. In the second category, pronounced differences are observed between the KERDs obtained with isoelectronic N${}^{q+}$ and O${}^{(q+1)+}$ ($q=3,5,7$) projectiles. These results provide direct evidence that projectile electronic structure plays a critical role in multielectron capture collisions.

Under review in Physical Review A