Positive ion production in single collisions of Cl− with rare gas atoms

The cross section σ−+ for double electron detachment from Cl− in a single collision with a rare gas atom has been measured between 12.5 and 122.5 keV. The magnitude of these cross sections shows that there is a good probability that a second electron will be emitted in collisions that detach one electron, particularly with light targets. The centre-of-mass cross section decreases with increasing target mass, but the variation is less than that for F− and O− double electron detachment cross sections.