HIGHLY SELECTIVE-POPULATION OF SPIN-ORBIT LEVELS IN ELECTRONIC AUTOIONIZATION OF O2

The dynamics of electronic autoionization in O2 has been studied using a new apparatus which combines a free-jet supersonic expansion with synchrotron radiation. Ions and electrons were analyzed by a double time-of-flight spectrometer. The spin-orbit sublevels of the H 3-PI-u (v = 0 and 2) Rydberg states in O2 were selectively excited and the resulting O2+ final states were determined by time-of-flight photoelectron spectroscopy. A strong variation of the 2-PI-1/2g:2-PI-3/2g branching ratio was observed. This variation results from the selection of a single continuum wave function in the autoionization process.