Angular anisotropy in the resonant Auger decay of 2p-photoexcited Mg

We have measured strongly negative β values of the 3s-participator lines at the magnesium 2p→4s and 2p1/2→3d excitations. Observed β values of the spectator lines following 2p→4s excitation are not reproduced by the strict spectator model. Our multiconfiguration Dirac-Fock calculations show that the resonant Auger spectra are influenced by unusually pronounced configuration interaction in the excited state. This influence is strongly enhanced by a change of sign in the Auger amplitude of the leading term near the transition energy, a dynamic effect similar to a Cooper minimum in photoionization

Natural widths in open-shell atoms: The K absorption spectrum of atomic oxygen

Total-ion-yield measurements and Hartree-Fock calculations are presented for the 1s→np, n=2 to 5 photoexcitations in atomic oxygen. Energies and relative intensities of the [1s]2s22p4(4P)np and [1s]2s22p4(2P)np series members are determined, and the apparent linewidths 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 theoretical input. The linewidth for the six individual components contained in the 1s→2p transition is determined to be 140(9) meV

Nonlinear dispersion in resonant Auger decay of H₂O molecules

We have measured the resonant Auger decay spectrum of the water molecule at the oxygen K edge. Strong deviations from the expected linear dispersion of the participator lines (which correspond to single-hole valence states) are observed. In a simplified picture the effect can be attributed to the combined effect of the intermediate- and final-state potential curves

Subnatural Linewidths in Core Level Excitation Spectra

We have measured a core excitation spectrum on the N2 1s→π* transition in which the experimental linewidth is limited by the instrumental resolution rather than by the lifetime of the core hole. The measurement is performed by recording the partial yield of resonant Auger electrons within a fixed kinetic energy window. The factors contributing to the line shape and the general applicability of the method are discussed

Natural Widths In Open-Shell Atoms: The K Absorption Spectrum Of Atomic Oxygen

Total-ion-yield measurements and Hartree-Fock calculations are presented for the 1s-- \u3enp, n=2 to 5 photoexcitations in atomic oxygen. Energies 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 linewidths 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 theoretical input. The linewidth for the six individual components contained in the 1s--\u3e2p transition is determined to be 140(9) meV