Product state control of bi-alkali chemical reactions

TL;DR

This paper explores controlling ultracold bi-alkali molecule reactions using external fields, showing that reaction pathways can be selectively suppressed or enabled by tuning energy release, thus offering precise reaction control.

Contribution

It demonstrates that electric and microwave fields can be used to control reaction channels of ultracold KRb molecules by tuning the energy release of the bond-swapping reaction.

Findings

Reactions are energetically forbidden to form trimers in ultracold conditions.

External fields can tune the reaction energy to zero, enabling control over reaction pathways.

Reaction channels can be selectively suppressed or activated using electric or microwave fields.

Abstract

We consider ultracold, chemically reactive scattering collisions of the diatomic molecules KRb. When two such molecules collide in an ultracold gas, we find that they are energetically forbidden from reacting to form the trimer species K$_2$Rb or Rb$_2$K, hence can only react via the bond-swapping reaction 2KRb $\to$ K$_2$ + Rb$_2$. Moreover, the tiny energy released in this reaction can in principle be set to zero by applying electric or microwave fields, implying a means of controlling the available reaction channels in a chemical reaction.