Heidelberg 2015 – scientific programme

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A: Fachverband Atomphysik

A 42: Ultracold Plasmas and Rydberg Systems III (with Q)

A 42.5: Talk

Friday, March 27, 2015, 12:00–12:15, P/H2

Rydberg-Electron Assisted Molecule Formation in Ultracold Atomic Clouds — •Thomas Niederprüm, Torsten Manthey, Oliver Thomas, Tobias Weber, and Herwig Ott — Technische Universität, Kaiserslautern

The continuously improving level of experimental control allows for the realization of excitations to increasingly high principle quantum numbers inside of cold atomic clouds. As the size of a Rydberg atom as well as it’s lifetime increases with the principal quantum number, it eventually enters a regime where it is likely to interact with the thermal ground state atoms surrounding it. At large distances this interaction is dominated by the scattering of the Rydberg electron with the ground state atom. At small internuclear separations however the 1/r4 - interaction between the ionic core of the Rydberg atom and the ground state atom is the leading contribution. The combined potential efficiently transports ground state atoms entering the Rydberg electrons wavefunction towards the ionic core. Approaching each other the ionic core and the ground state atom can undergo resonant dipole energy exchange and form an ionic Rb₂⁺ molecule while the Rydberg electron gains the binding energy of the molecule and escapes. We report on the creation of such molecular ions in dense thermal clouds of ⁸⁷Rb under excitation to Rydberg p-States. Furthermore a systematic study on the density dependence of the molecule production for various principal quantum numbers enables us to obtain the effective cross section for the molecule formation process as well as it’s scaling behavior.