Evidence of Dynamical Effect on Molecular Autoionization from He+ Impact on He

Measurements have been done for ejected-electron spectra from 5-27-keV ${\mathrm{He}}^{+}$ impact on He. A bandlike structure is observed in the higher-energy part of the spectra and theoretically reproduced as a result of molecular autoionization of ${\mathrm{He}}_{2}^{+}$. The value of autoionization width ${\overline{\ensuremath{\Gamma}}}_{A}$ is closely proportional to the energy of the incident ${\mathrm{He}}^{+}$ ion. This result leads to the conclusion that the dominant process for the observed molecular autoionization is due to the dynamical couplings.