Stark Shifts in the Spectra of Long-Range Rydberg Molecules

Michael Peper, Martin Trautmann, Johannes Deiglmayr

We present a mechanism contributing to the detection of photoassociated long-range Rydberg molecules via pulsed-field ionization: ionic products, created by the decay of a long-range Rydberg molecule, modify the excitation spectrum of surrounding ground-state atoms and facilitate the excitation of further atoms into Rydberg states by the photoassociation light. Such an ion-mediated excitation mechanism has been previously called a Coulomb antiblockade. Pulsed-field ionization typically does not discriminate between the ionization of a long-range Rydberg molecule and an isolated Rydberg atom, and thus the number of atomic ions detected by this mechanism is not proportional to the number of long-range Rydberg molecules present in the probe volume. By combining high-resolution UV and rf spectroscopy of a dense, ultracold gas of cesium atoms, theoretical modeling of the molecular-level structures of long-range Rydberg molecules bound below $n\phantom{\rule{0.16em}{0ex}}^{2}P_{3/2}$ Rydberg states of cesium, and a rate model of the photoassociation and decay processes, we unambiguously identify the signatures of this detection mechanism in the photoassociation of long-range Rydberg molecules bound below atomic asymptotes with negative Stark shifts.

Jovica Stanojevic, Robin C ot 'e

Jovica Stanojevic, Robin Côté, D. Tong +3 more

Markus Deiß, Shinsuke Haze, Johannes Hecker Denschlag

We present a novel binding mechanism where a neutral Rydberg atom and an atomic ion form a molecular bound state at a large internuclear distance. The binding mechanism is based on Stark shifts and level crossings that are induced in the Rydberg atom due to the electric field of the ion. At particular internuclear distances between the Rydberg atom and the ion, potential wells occur that can hold atom–ion molecular bound states. Apart from the binding mechanism, we describe important properties of the long-range atom–ion Rydberg molecule, such as its lifetime and decay paths, its vibrational and rotational structure, and its large dipole moment. Furthermore, we discuss methods of how to produce and detect it. The unusual properties of the long-range atom–ion Rydberg molecule give rise to interesting prospects for studies of wave packet dynamics in engineered potential energy landscapes.

Hyunwook Park, Thomas F. Gallagher

Chris H. Greene, Matthew T. Eiles

The authors present a method based on the Coulomb Green's function to derive the electronic structure of ultra-long-range Rydberg molecules including spins, providing a promising alternative to the standard method based on basis-set expansion, which was shown to have serious convergence problems. Use of this approach should enable more accurate studies of Rydberg-molecule spectra and the electron-atom scattering phase shifts upon which they depend.