Giant cross section for molecular ion formation in ultracold Rydberg gases

TL;DR

This paper reports a significantly enhanced associative ionization cross section in ultracold Rydberg gases, driven by electron-mediated mass transport, with the cross section vastly exceeding the molecule's geometric size.

Contribution

It reveals a giant cross section for molecular ion formation in ultracold Rydberg gases, highlighting the role of Rydberg electron dynamics in reaction kinetics.

Findings

Cross section is three orders of magnitude larger than molecular size

Reaction enhancement is due to electron-mediated mass transport

Inelastic scattering cross section matches Rydberg electron wavefunction size

Abstract

We have studied the associative ionization of a Rydberg atom and a ground state atom in an ultracold Rydberg gas. The measured scattering cross section is three orders of magnitude larger than the geometrical size of the produced molecule. This giant enhancement of the reaction kinetics is due to an efficient directed mass transport which is mediated by the Rydberg electron. We also find that the total inelastic scattering cross section is given by the geometrical size of the Rydberg electron's wavefunction.