L. Journel

Hollow-atom - hollow-ion decay routes of triply excited lithium: first Auger results and a comparison with R-matrix calculations

We present the first photoelectron results for hollow-atom - hollow-ion decay paths of triply excited lithium, in which the hollow lithium atoms decay via hollow and then to ions. The high-resolution data, obtained at the 9.01 beamline of the Advanced Light Source at Berkeley, provide considerable insight into the decay pattern of the various hollow lithium resonances. Tracking the secondary Auger decays as functions of the incident photon energy provides new data on triply excited resonances. The results compare favourably with recent advanced R-matrix calculations. Detection of the individual Auger decay lines also provides information on the energies and widths of a number of doubly excited levels of the ion.

A dedicated electron spectrometer for photoionization studies of atomic ions with synchrotron radiation

Abstract A cylindrical mirror analyzer (CMA) dedicated to the photoionization on atomic ions of experiments, has been designed using a new semi-analytical method. A direct comparison between the calculated and measured intensities of the emitted photoelectrons is given. Finally, the improvement of the new experimental set-up will be illustrated by the first angle-resolved photoelectron spectra obtained in the photoionization of an ion beam.

Present status of inner-shell photoionization studies in singly- and multiply-charged atomic ions

Abstract Our present knowledge of ionic photoionization is critically reviewed. The inadequacy of theoretical calculations based on the independent-particle model for low- and medium-charge state ions is demonstrated, emphasizing the need for measurements of total and partial photoionization cross sections in singly- and multiply-charged ions. The experimental techniques for obtaining photoabsorption, photoionization, and photoelectron spectra of ionized species are described and some selected examples are discussed. The perspectives opened up by the use of an ECR ion source in combination with the radiation emitted by undulators of third-generation storage rings are sketched out.

Photoelectron spectroscopy experiments on singly charged positive-ions using synchrotron radiation

Abstract The first angle-resolved photoelectron spectroscopy experiments on singly charged ions using synchrotron radiation are described. The feasibility of these experiments has been demonstrated for resonant photoionisation of Ca+ ions by use of the high flux of photons available from an undulator. These experiments open new opportunities for the detailed study of photoionisation processes in ionic species.