[en] Most of the matter in the universe (> 99.99%) exists in a highly ionized state. However, relatively little experimental data is available on the structure of multiply charged ions and their interactions with photons. Combining a merged ion-photon beam (IPB) endstation, an electron-cyclotron- resonance (ECR) ion source and a third-generation synchrotron radiation source makes possible quantitative studies of photoionization (PI) of multiply charged ions. This apparatus is permanently installed on undulator beamline 10.0.1.2 at the Advanced Light Source (ALS), which provides intense photon beams at high energy resolution range 17 - 340 eV. In the soft X-ray region we can study the atomic structure of the inner shells for most of the elements, which has not explored yet for the best of my knowledge. Photoionization of molecular and cluster ions remain essentially unexplored, and will provide new insights into their structure and dynamics. Interpreting such experiments will be a major challenge. So SESAME as a third generation light source similar to the ALS will be the best for such studies, and with similar IPB endstation at the ALS will attract many researchers from the region and all over the world. PI experiments performed at ALS in collaboration with the Giessen group included multiply charged metallic ions, such as K-like Sc²⁺, for which complementary measurements of time-reversed process electron-Sc³⁺ recombination have been performed at a heavy-ion storage ring in Europe. PI measurements for the lower charge states of the Fe isonuclear sequence, which are important for astrophysical applications, and present a formidable theoretical challenge. Many other examples will be presented during the meeting and the future look of PI spectroscopy. (author)

[en] Absolute photoionization cross-section measurements for a mixture of ground and metastable states of Xe4+, Xe5+, and Xe6+ are reported in the photon energy range of 4d->nf transitions, which occur within or adjacent to the 13.5 nm window for extreme ultraviolet lithography light source development. The reported values allow the quantification of opacity effects in xenon plasmas due to these 4d nf autoionizing states. The oscillator strengths for the 4d->4f and 4d->5f transitions in Xeq+ (q=1-6) ions are calculated using nonrelativistic Hartree-Fock and random phase approximations. These are compared with published experimental values for Xe+ to Xe3+ and with the values obtained from the present experimental cross-section measurements for Xe4+ to Xe6+. The calculations assisted in the determination of the metastable content in the ion beams for Xe5+ and Xe6+. The experiments were performed by merging a synchrotron photon beam generated by an undulator beamline of the Advanced Light Source with an ion beam produced by an electron cyclotron resonance ion source

[en] Most of the matter in the universe (>99.99%) exists in a highly ionized state. However, relatively little experimental data is available on the structure of multiply charged ions and their interactions with photons. Combining a merged ion-photon beam (IPB) endstation, an electroncyclotron- resonance (ECR) ion source and a third-generation synchrotron radiation source makes possible quantitative studies of photoionization (PI) of multiply charged ions. This apparatus is permanently installed on undulator beamline 10.0.1.2 at the Advanced Light Source (ALS), which provides intense photon beams at high energy resolution range 17 - 340 eV. In the soft X-ray region we can study the atomic structure of the inner shells for most of the elements, which has not explored yet for the best of my knowledge. Photoionization of molecular and cluster ions remain essentially unexplored, and will provide new insights into their structure and dynamics. Interpreting such experiments will be a major challenge. So SESAME as a third generation light source similar to the ALS will be the best for such studies, and with similar IPB endstation at the ALS will attract many researchers from the region and all over the world. PI experiments performed at ALS in collaboration with the Giessen group included multiply charged metallic ions, such as K-like Sc²⁺, for which complementary measurements of time-reversed process electron-Sc³⁺ recombination have been performed at a heavy-ion storage ring in Europe. PI measurements for the lower charge states of the Fe isonuclear sequence, which are important for astrophysical applications, and present a formidable theoretical challenge. Many other examples will be presented during the meeting and the future look of PI spectroscopy

No abstract available

No abstract available

[en] We have investigated valence-shell photoionization (PI) of ¹S ground state and ³P^o metastable states of C²⁺ ions. Absolute PI cross-sections were measured in the range 40.7-56.4 eV with an energy spread of 30 meV using a photon-ion merged beams arrangement at the Advanced Light Source (ALS). Detailed calculations based on the semi-relativistic Breit-Pauli R-matrix approach suggest a fraction of 40% of metastable ions in the primary beam of the experiment. Additional high resolution measurements have been carried out with an energy spread as low as 7.5 meV. The new data permit a sensitive test of theory with respect to the individual PI cross-section contributions originating from the different ³P_0,1,2 fine-structure components of the initial triplet states

[en] Photoionization of multiply charged ions is studied using the merged-beams technique at the Advanced Light Source. Absolute photoionization cross sections have been measured for a variety of ions along both isoelectronic and isonuclear sequences

[en] Absolute cross-section measurements for resonant double photoexcitation of Li+ ions followed by autoionization have been performed at high resolution in the photon energy range from 148 eV, just below the (2s2p, 2(0,1)n+) resonance, to 198 eV (the region of the double ionization threshold). The measurements have been made using the photon-ion merged-beam endstation at the Advanced Light Source, Lawrence Berkeley National Laboratory, USA. The absolute cross-section measurements show excellent agreement with theoretical results from the R-matrix plus pseudo-state (RMPS) method. Comparisons between theory and experiment for the Auger resonance energies, autoionization linewidth (?)and the Fano line profile index q for several members of the principal(2snp, 2(0, 1)n+) and (3snp, 3(1,1)n+) Rydberg series found in the photoionization spectra for the 1Po symmetry show satisfactory accord

[en] The principle of microscopic time-reversal of physical processes, detailed balance, is widely used and depended upon in the theoretical community as a connection between the inverse processes of photorecombination (PR) and photoionization (PI). This paper reports on a novel use of detailed balance and the comparison of experimental results obtained by two very distinct techniques to determine both the metastable fraction of an ion beam and partial Sc³⁺ PR cross sections and partial Sc²⁺ PI cross sections for the ground state and for two metastable states. The Sc²⁺ to Sc³⁺ system presents a unique opportunity to obtain comprehensive state-selective information by combining results from PR and PI experiments

[en] Photoionization and electron-impact ionization of Xe³⁺ ions in the region of 4d inner-shell excitation-autoionization have been studied using interacting-beam spectroscopic techniques. Absolute cross sections for photoionization of Xe³⁺ have been obtained and the electron-impact spectrum has been normalized to previously published absolute data. The Xe³⁺ spectra show large contributions from 4d→nf excitation-autoionization processes compared to the lower charge states of Xe due to the significant collapse of the nf wave functions into the ion core as the initial charge state of the ion is increased. In addition, a tentative value for the ionization potential of Xe³⁺ of 42.2±0.2 eV was obtained