Observation of radiative double electron capture for

Radiative double electron capture (RDEC), occurring when two electrons are captured to a projectile ion with the simultaneous emission of a single photon, has been investigated. RDEC can be considered as the time inverse process of double photoionization. Strong evidence for RDEC is found in F 9+ + N 2 collisions and additionally for one‐electron F 8+ for which the probability for the process is expected to be considerably smaller. Preliminary values for the cross sections for RDEC have been determined. A significant advantage of the gas target is that multiple‐collision effects seen for a solid target are avoided due to the single‐collision conditions that prevail for gas targets.