Theoretical studies of hydrogen Rydberg atoms in electric fields

David A. Harmin

Patrick H. Donnan, F. Robicheaux

We have calculated the rates for the processes that result from collisions of positrons with Rydberg atoms in strong magnetic fields. This is the first step in a two-stage charge transfer, which is being explored as a mechanism for the formation of cold anti-hydrogen. Unlike previous theoretical explorations we have also investigated the cases when the energy of the positrons can be comparable to or larger than the binding energy of the atom. We have also examined how big an electric field is needed to destroy the resulting positronium. We find that the charge transfer does not scale as for n = 40 states for positron temperatures above T ∼ 25 K. Also, we find that the positronium atoms are more easily destroyed by electric fields if they emerge from the charge transfer along the magnetic field lines, contrary to what might be expected for the effective electric field. Both results have implications for the formation of anti-hydrogen atoms.

R. F. Stebbings, F. B. Dunning

List of contributors Preface 1. Rydberg atoms in astrophysics A. Dalgarno 2. Theoretical studies of hydrogen Rydberg atoms in electric fields R. J. Damburg and V. V. Kolosov 3. Rydberg atoms in strong fields D. Kleppner, Michael G. Littman and Myron L. Zimmerman 4. Spectroscopy of one- and two-electron Rydberg atoms C. Fabre and S. Haroche 5. Interaction of Rydberg atoms with blackbody radiation T. F. Gallagher 6. Theoretical approaches to low-energy collisions of Rydberg atoms with atoms and ions A. P. Hickman, R. E. Olson and J. Pascale 7. Experimental studies of the interaction of Rydberg atoms with atomic species at thermal energies F. Gounand and J. Berlande 8. Theoretical studies of collisions of Rydberg atoms with molecules Michio Matsuzawa 9. Experimental studies of thermal-energy collisions of Rydberg atoms with molecules F. B. Dunning and R. F. Stebbings 10. High-Rydberg molecules Robert S. Freund 11. Theory of Rydberg collisions with electrons, ions and neutrals M. R. Flannery 12. Experimental studies of the interactions of Rydberg atoms with charged particles J. -F. Delpech 13. Rydberg studies using fast beams Peter M. Koch Index.

Baiwen Li

S. Feneuille

Tony van der Veldt, W. Vassen, W. Hogervorst

The n=60, L z =0 angular momentum manifold in helium is studied in the presence of an electric field parallel to a fixed magnetic field (B=0.1539 T). Results obtained from a CW laser-atomic beam experiment are compared with diagonalization calculations and with a WKB approximation including core effects. Core-induced anticrossings have been analysed in detail. The supersymmetry, including quasi-crossings in hydrogen to occur at the same value of the electric field strength, does not apply for L z =0 manifolds in non-hydrogenic Rydberg atoms.