Chemical pathways in ultracold reactions of SrF molecules

TL;DR

This paper theoretically investigates ultracold SrF molecule reactions, revealing that only a specific fluorine transfer reaction is energetically feasible and barrierless at ultralow temperatures.

Contribution

It identifies the only energetically allowed reaction pathway for SrF molecules at ultracold temperatures and demonstrates its barrierless nature through theoretical calculations.

Findings

Bond swapping is energetically forbidden at ultracold temperatures.

The only allowed reaction is SrF + SrF → SrF₂ + Sr.

The reaction proceeds without an energy barrier via fluorine transfer.

Abstract

We present a theoretical investigation of the chemical reaction SrF + SrF $\rightarrow$ products, focusing on reactions at ultralow temperatures. We find that bond swapping, SrF + SrF $\rightarrow$ Sr$_2$ + F$_2$, is energetically forbidden at these temperatures. Rather, the only energetically allowed reaction is SrF + SrF $\rightarrow$ SrF$_2$ + Sr, and even then only singlet states of the SrF$_2$ trimer can form. A calculation along a reduced reaction path demonstrates that this abstraction reaction is barrierless, and proceeds by one SrF molecule "handing off" a fluorine atom to the other molecule.