We measured the ${\mathrm{Ne}}^{q+}$ charge-state yield distribution for Ne atoms multiply ionized by 1-MeV/amu ${\mathrm{H}}_2^{+},$ in coincidence with the final state of the projectile, for both breakup and nonbreakup channels. Measurements with 1-MeV ${\mathrm{H}}^{+}$ projectiles were also performed. While the ${\mathrm{H}}_2^{+}$ nonbreakup channel produces results similar to equal-velocity proton or electron projectiles, the breakup channels lead to a charge-state yield distribution very close to the known Ne ${2s}^{-1}$ postcollisional decay distribution, measured through photoionization [T. A. Carlson, W. E. Hunt, and M. O. Krause, Phys. Rev. 151, 41 (1966)]. This behavior suggests that, in the breakup channels, contributions to multiple ionization from mechanisms that are usually considered to be dominant in ion-atom collisions are less important than the postcollisional decay.

• Received 3 April 2003

DOI:https://doi.org/10.1103/PhysRevA.68.042707