PAMOP: Petascale atomic, molecular and optical collision calculations

Petaflop architectures are currently being utilized efficiently to perform large scale computations in Atomic, Molecular and Optical Collisions. We solve the Schr\"odinger or Dirac equation for the appropriate collision problem using the R-matrix or R-matrix with pseudo-states approach. We briefly outline the parallel methodology used and implemented for the current suite of Breit-Pauli and DARC codes. In this report, various examples are shown from our theoretical results compared with experimental results obtained from Synchrotron Radiation facilities where the Cray architecture at HLRS is playing an integral part in our computational projects.Comment: 16 pages, 6 figures, Chapter 4, in High Performance Computing in Science and Engineering 2014, edited by W. E. Nagel, D. B. Kroner, and M. Reich (Springer, New York and Berlin, 2014). http://www.springer.com/mathematics/computational+science+%26+engineering/book/978-3-319-10809-

Electron-impact ionization of W5+

Electron-impact single-ionization cross sections for the W5+ ion have been studied experimentally and theoretically. Measurements of a detailed ionization spectrum and of absolute cross sections were performed employing the crossed-beams method in the energy range from the ionization onset up to 1000 eV. The experimental data show a prominent contribution of W5+ ions in metastable states. The theoretical analysis includes level-to-level calculations from the 4f145s25p65d ground configuration and long-lived levels of the 6s, 5p55d2, 4f135d2, and 4f135d6s configurations. Direct-ionization and excitation-autoionization contributions to the total single-ionization cross sections were calculated employing a distorted-wave approximation. Radiative damping was taken into account. It is shown that correlation effects play an important role and lead to substantial reduction of cross sections. Theory and experiment are in quite good agreement when, within a statistical model, a (85±9)% fraction of parent ions in the ground configuration is assumed. The strongest contributions of metastable parent ions arise from the 5p55d2 and 4f135d2 configurations.The experimental part of this study was supported by the Deutsche Forschungsgemeinschaft under Project No. Mu 1068/20. M.F.G. acknowledges the Deutsche Forschungsgemeinschaft for supporting his research stays at the Gießen Institut für Atom-und Molekülphysik through Grants No. Mu-1068/19 and No. Mu-1068/21. A.B. is supported by the German Federal Ministry of Education and Research (BMBF) through Grant No. 05P19RGFA1. Part of the computations were performed using resources of the High Performance Computing Center “HPC Sauletekis” in Vilnius University Faculty of Physics. We thank K. Spruck, A. Becker, J. Hellhund, and J. Rausch for their help in the present experimental program.Scopu

Photoionization of Sc2+ ions by synchrotron radiation: High resolution measurements and absolute cross sections in the photon energy range 23-68 eV

Cross sections for photoionization of doubly-charged scandium ions has been measured using a merged-beams technique. Results are compared with the time-reversed process of photorecombination

Physics book: CRYRING@ESR

The exploration of the unique properties of stored and cooled beams of highly-charged ions as provided by heavy-ion storage rings has opened novel and fascinating research opportunities in the realm of atomic and nuclear physics research. Since the late 1980s, pioneering work has been performed at the CRYRING at Stockholm (Abrahamsson et al. 1993) and at the Test Storage Ring (TSR) at Heidelberg (Baumann et al. 1988). For the heaviest ions in the highest charge-states, a real quantum jump was achieved in the early 1990s by the commissioning of the Experimental Storage Ring (ESR) at GSI Helmholtzzentrum für Schwerionenforschung (GSI) in Darmstadt (Franzke 1987) where challenging experiments on the electron dynamics in the strong field regime as well as nuclear physics studies on exotic nuclei and at the borderline to atomic physics were performed. Meanwhile also at Lanzhou a heavy-ion storage ring has been taken in operation, exploiting the unique research opportunities in particular for medium-heavy ions and exotic nuclei (Xia et al. 2002)