Photodetachment Cross Section and the Electron Affinity of Atomic Oxygen

Experiments and theory on the continuous absorption of radiation by atomic-oxygen negative ions are described and discussed. The absorption cross section for photon energies not too near threshold is obtained directly from one of the experiments. Theory and experiment are combined to give the cross section in the vicinity of threshold and a precise value of the electron affinity of atomic oxygen. The latter result is EA (O) = 1. 4650. 005 ev. The data are used for computation of the radiative attachment coefficient, and other applications of the experimental results are discussed.