PHOTOIONIZATION OF ATOMIC OXYGEN AT THE MULTIPLET TERM LEVEL FROM 20 TO 212 EV

The valence shell photoionization branching ratios of atomic oxygen ar e measured at the multiplet term level in a synchrotron-radiation-base d electron spectrometry experiment and calculated using the multiconfi guration Hartree-Fock (MCHF) method for photon energies between 20 and 212 eV. The 2p(S-4,D-2,P-2) branching ratios, 2sP-2 to 2sP-4 in tensity ratio, and 2s to 2p cross-section ratio for removal of a 2 s of 2p electron are presented, and satisfactory agreement between the experiment and the MCHF calculation is found. In addition, the relati ve photoionization cross section is measured between 24 and 122 eV and is compared with calculations and a previous absolute cross-section m easurement. Good agreement between the experimental and MCHF results i s seen.