We have studied the multielectron processes in close collisions between slow ${\mathrm{Ne}}^{q+}$ ions ($q=1–9$, energies of 5 and $14\mathrm{keV}$) and Ar atoms through measurements of the charge-state correlations between 27° scattered and 70° recoiling ions. At the selected scattering angle, the internuclear distance of the closest approach at $35\mathrm{keV}$ is comparable to the $L$-shell radius of Ar atoms. A drastic difference between low-charged $(q=1–3)$ and highly charged $(q=7–9)$ Ne ions was found. For example, the most probable channel for the ${\mathrm{Ne}}^{7+}$ projectile is three-electron capture accompanied with two-electron loss whereas for the ${\mathrm{Ne}}^{+}$ projectile pure double ionization was found most probable. As a general trend, the mean charges of the both ions and the mean number of captured electrons increase almost linearly with incident charge $q$, while the mean number of ejected electrons from the system is independent of $q$ at both 5 and $14\mathrm{keV}$. We also measured the charge state distributions of the Ar recoil ions as function of the ${\mathrm{Ne}}^{q+}$ ($q=3$, 5, and 7) energies between 5 and $63\mathrm{keV}$, which corresponds to distances of closest approach between $0.6\mathrm{a.u.}$ and $0.17\mathrm{a.u.}$ We found that the charge of the Ar ions increases at internuclear distances less than $0.32\mathrm{a.u.}$

• Received 1 June 2006

DOI:https://doi.org/10.1103/PhysRevA.75.032722