ArLAuger-electron emission in 0.4-, 0.8-, and 1.6-MeVAr+-Kr andKr+-Ar collisions

Abstract

The electron-energy spectra for electrons emitted from ${\mathrm{Ar}}^{+}$-Kr and ${\mathrm{Kr}}^{+}$-Ar collisions have been measured for projectile energies of 0.4, 0.8, and 1.6 MeV. The spectra show a peak, or peaks, attributable to L-vacancy production in the AR ions superimposed on a continuous portion of the electron spectra. This continuous portion, which decreases with increasing electron energy, extends to electron energies in the 600--800-eV range. The data show some events for which electrons with more than twice the normal ${\mathit{L}}_{2,3}$-MM Auger energies are emitted, and their origin is not clear. They might be due to the decay of ${\mathit{L}}_{1}$ vacancies or to the filling of a vacancy in a molecular orbital during the collision. An Auger process in which two 2p vacancies are filled with the subsequent emission of only one electron, an ${\mathit{L}}_{2,3}$${\mathit{L}}_{2,3\mathrm{\ensuremath{-}}}$MMM transition, might contribute to the spectra above 400 eV. The association of the major peak with Ar L-vacancy production is in contrast to a recent paper in which the peak, together with the higher energy electrons, was attributed to quasimolecular electron emission, specifically, filling of 4s\ensuremath{\sigma} and 4p\ensuremath{\pi} molecular-orbital vacancies during the collision.