Measurements of cross sections for the ionization of Mg+ to Mg2+ by electron impact

Cross sections have been measured for the reaction Mg + + e -> Mg 2 + 2e for electron energies between threshold and 2000 eV; the errors are estimated to be less than ±10% for electron energies greater than 50 eV. The cross section σ attains a maximum value 4·85 × 10 -17 cm 2 (±11%) at 35 eV, and, when E is greater than 11, it obeys the law σ E = 9·8 × 10 -16 lg (0·216 E ) cm 2 , where E is the incident electron energy in units of the ionization energy of Mg + (15·03 eV). No irregularities in the ionization function were found which could be attributed to autoionization.