Darmstadt 2008 – scientific programme
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A: Fachverband Atomphysik
A 25: Posters: Precision spectroscopy of atoms and ions
A 25.8: Poster
Thursday, March 13, 2008, 16:30–18:30, Poster C3
Two–photon decay rates for highly–excited ionic states — •Andrey Surzhykov1,2 and Ulrich D. Jentschura1 — 1Max–Planck–Institut für Kernphysik, Heidelberg — 2École Normale Supérieure, Paris
Even though the two–photon decay of hydrogen–like ions has been under intense investigations for more than a half century, the analysis of this process still raises a number of unresolved problems. The problems concern, for example, the two–photon transition from the excited into the ground state which passes the real intermediate state [1]. Such a transition leads to the narrow resonances in the energy spectrum of emitted photons. The proper treatment of these resonances is required for computing the total decay rates obtained after an integration over the energy of one of the emitted photons. In our contribution, therefore, we present a quantum electrodynamical approach based on on a careful mathematical handling of the resonances infinitesimally displaced from the photon integration contour [2]. By making use of this approach, we obtain the finite, physically sensible results for the decay rates of the two–photon 3s → 1s and 4s → 1s transitions in neutral hydrogen as well as in hydrogen–like xenon Xe53+ and uranium U91+ ions.
[1] J. D. Cresser et al., Phys. Rev. A 33 (1986) 1677.
[2] U. D. Jentschura, J. Phys. A 40 (2007) F223.