Charge-changing processes have been investigated for 267–320-MeV ${\mathrm{Ti}}^{19+}$ and ${\mathrm{Ti}}^{20+}$ ions channeled in a thin gold crystal. High-resolution measurements of the energy losses suffered by the charge-changed ions show that electron capture by the well-channeled particles is significantly enhanced when the projectile velocity corresponds to ejected KLL Auger-electron energies from doubly excited states in the rest frame of the ion. The measurements of dielectronic capture exhibit exceedingly narrow resonance widths and reveal a shift of the resonances toward higher energies.

• Received 11 October 1989

DOI:https://doi.org/10.1103/PhysRevLett.64.380