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Observation of Spin-Singlet Butterfly Rydberg Molecules in an Ultracold Atomic Rb Gas
Markus Exner1, Rohan Srikumar2, Richard Blättner1
1Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, Department of Physics and Research Center OPTIMAS, 67663 Kaiserslautern, Germany.
None:
We report the observation of spin-singlet ultralong-range Rydberg butterfly molecules consisting of a ground-state atom bound to a Rydberg atom by P-wave scattering of ^{87}Rb Rydberg electrons from ^{87}Rb(5 s) atoms. A three-photon excitation scheme enables the photoassociation of these molecules by weakly admixing Rb(18f_{7/2}) states. The measured binding energies, kilo-Debye permanent electric dipole moments, and lifetimes are in excellent agreement with theory. Two long-lived vibrational levels, red detuned from the Rb(18f_{7/2}) threshold, are observed. This experiment is a foundational step in the production of ultracold anions and heavy Rydberg ion-pair systems.
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