Absolute cross section for photoionization of atomic oxygen

The absolute cross section for photoionization of atomic oxygen from the 2p4 3P ground state of O(0) to the 2p3 4S ground state of O(+) has been measured at five narrow wavelength intervals between 89.8 and 76.2 nm. The cross section near the 2p3 4S threshold is 4.5 Mb + or - 7%. Recent calculations by Taylor and Burke (1976) and by Pradhan and Saraph (1977) are in reasonable agreement with this work. The dipole-length results of Taylor and Burke (4.1 Mb) are in better agreement with the experiment than their dipole-velocity results (3.2 Mb).