Abstract
Absolute total cross sections for electron-impact single ionization of , , and ions have been measured using a crossed-beams technique from below threshold to 500, 400, and 500 eV, respectively, with absolute uncertainties of 12% or less. The measured cross sections are in good agreement with distorted-wave calculations and show significant contributions from excitation autoionization. Nonzero cross sections below threshold for the and ions suggest the presence of metastable ions in those two species that were extracted from an electron-cyclotron-resonance ion source. Such evidence of metastable ions was not found in the case of the ion measurment.
- Received 20 December 1993
DOI:https://doi.org/10.1103/PhysRevA.49.4676
©1994 American Physical Society