Abstract
Cross sections for electron-impact single and double detachment from have been measured from 0 to 200 eV. The single-detachment cross section peaks at 4–5 eV with a cross-section maximum of about . A state has recently been predicted to give rise to a resonance state in the dianion [T. Sommerfeld et al., Phys. Rev. A 55 1903 (1997)]. We observe no resonances in the detachment cross section of and hence no sign of an equivalent shortlived state. The ratio of the double- to single-detachment cross section reaches a constant value of 3% at energies above 50 eV. A simple model relates this number to a shake-off probability of about 90%. The ratio between double and single ionization of neutral atomic targets at high energy is also discussed, and the model relates this ratio to the shake-off probability in the sudden approximation.
- Received 30 April 1998
DOI:https://doi.org/10.1103/PhysRevA.58.2819
©1998 American Physical Society