NATURAL WIDTHS IN OPEN-SHELL ATOMS - THE K-ABSORPTION-SPECTRUM OF ATOMIC OXYGEN

Total-ion-yield measurements and Hartree-Fock calculations are present ed for the 1s-->np, n=2 to 5 photoexcitations in atomic oxygen. Energi es and relative intensities of the [1s]2s(2)2p(4)(P-4)np and [1s]2s(2) 2p(4)(P-2)np series members are determined, and the apparent linewidth s are measured. It is shown that natural widths in an open-shell atom can be deduced from an absorption spectrum only with the aid of theore tical input. The linewidth for the six individual components contained in the 1s-->2p transition is determined to be 140(9) meV.