ANGULAR-DISTRIBUTIONS IN AUTODETACHMENT FROM DOUBLY-EXCITED O- STATES

The angular distributions of electrons ejected from collisionally exci ted O- ions have been measured in order to test the previous assignmen ts of excited states for this ion. The angular distributions support t he interpretation that the two dominant peaks in the electron-energy s pectrum represent the autodetachment of the 2p3(2D)3s22D0 state, decay ing to the 3P and 1D states of the oxygen ground-state configuration, with an experimental branching ratio of 1.58 +/- 0.08, and not that tw o different autodetaching states are populated, as previously assumed. Theoretical calculations are in good agreement with the experimental findings.