RADIATIVE STABILIZATION IN DOUBLE-ELECTRON CAPTURE TO 4L4L' AND 4L5L'STATES IN O6+

Following slow collisions between O8+ and Ar, double-electron capture into 4l4l' and 4l5l' states of O6+ has been reported. The experimental results show that in 25% of the events the two electrons are retained on the oxygen presumably due to radiative stabilization. In order to understand this high rate of stabilization, we have calculated for the first time the decay properties of all the 4l4l' and 4l5l' terms in t he isolated atom using a truncated diagonalization method with B-splin e basis sets. The 4l4l' states are lying in the same range of energy a s the higher members of the 3lnl' Rydberg series and we have extended our B-spline approach to represent accurately the 3lnl' states with n up to 50. In this static approach, we obtain 30.8% radiative stabiliza tion for the 4l4l' manifold and 2.6% for the 4l5l' manifold assuming i n both cases a statistical population of the states. We conclude that these values, when combined with the experimentally determined initial populations of the two configurations, are too small to explain the e xperimental features assuming a statistical population distribution an d we propose that in order to clarify the situation an experimental an d/or theoretical study of the population distribution over the two con figurations is necessary.