EGAS41 - Swansea University

41 st EGAS PL 3 Gdańsk 2009
Observation of ultralong-range Rydberg molecules
V. Bendkowsky 1 , B. Butscher 1 , J. Nipper 1 , J. Shaffer 2 , R. Löw 1 , T. Pfau 1
1 5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57,70569 Stuttgart,
Germany
2 Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman,
Oklahoma 73072, USA
∗ Corresponding author: v.bendkowsky@physik.uni-stuttgart.de,
At ultralow temperatures – in so-called frozen Rydberg gases – the scattering of a Rydberg
electron and a nearby polarizable ground-state atom can generate an attractive
potential. In this case, the scattering-induced attractive interaction binds the groundstate
atom to the Rydberg atom at a well-localized position within the Rydberg electron
wavefunction (Fig. 1), and thereby yields giant molecules with internulear separations of
several thousand Bohr radii.
Here we report the spectroscopic characterization of such exotic molecular states
formed by rubidium Rydberg atoms that are in the spherically symmetric s state and
have principal quantum numbers, n, between 34 and 40. We find that the spectra of
the vibrational ground state and of the first excited state of the Rydberg molecule, the
rubidium dimer Rb(5s)-Rb(ns), agree well with simple model predictions. The data allow
us to extract the s-wave scattering length for scattering between the Rydberg electron
and the ground-state atom, Rb(5s), in the low-energy regime (E kin < 100meV), and to
determine the lifetimes and the polarizabilities of the Rydberg molecules [1].
Additionally, we report on the observation of trimer states, where even two groundstate
atoms are bound by a Rydberg atom.
Figure 1: Electron probability density and molecular potential for the state n=35, l=0.
References
[1] V. Bendkowsky et al., Nature 458, 1005 (2009)
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