A single ion as a three-body reaction center in an ultracold atomic gas

TL;DR

This study demonstrates that a single trapped Rb^+ ion can act as a catalytic center in three-body recombination with ultracold Rb atoms, significantly enhancing reaction rates and influencing molecular formation.

Contribution

It reveals the ion's role as a catalyst in three-body recombination, with energy-dependent rate coefficients and the ability to be regenerated after reactions.

Findings

The three-body recombination rate coefficient K_3 is about 1000 times larger than for neutral atoms.

Large energy releases up to 0.1 eV lead to ion ejection and subsequent sympathetic recooling.

The ionic product remains Rb^+, indicating catalytic behavior in molecule formation.

Abstract

We report on three-body recombination of a single trapped Rb^+ ion and two neutral Rb atoms in an ultracold atom cloud. We observe that the corresponding rate coefficient K_3 depends on collision energy and is about a factor of 1000 larger than for three colliding neutral Rb atoms. In the three-body recombination process large energies up to several 0.1eV are released leading to an ejection of the ion from the atom cloud. It is sympathetically recooled back into the cloud via elastic binary collisions with cold atoms. Further, we find that the final ionic product of the three-body processes is again an atomic Rb^+ ion suggesting that the ion merely acts as a catalyzer, possibly in the formation of deeply bound Rb_2 molecules.