Shake-off measurements of electron-ion-scattering phase shifts.

Abstract

Continuum electrons are produced in a specific l state with high-energy resolution using shake-off photoionization. This process is well characterized, so that the photoionization signal is an accurate measurement of the difference between the continuum electron's wave-function phase and that produced by a hydrogenic interaction. Measurements are reported showing the phase of a ${\mathrm{Ba}}^{+}$+${\mathrm{e}}^{\mathrm{\ensuremath{-}}}$ in a d wave, in cases where it is well behaved, and in cases where doubly excited resonances produce rapid phase variations.