The Geometric Phase Appears in the Ultracold Hydrogen Exchange Reaction

TL;DR

This study demonstrates that the geometric phase significantly influences the reactivity in ultracold hydrogen exchange reactions, with potential applications in controlling chemical reactions via external fields or nuclear spin states.

Contribution

It provides the first detailed quantum reactive scattering calculations showing the geometric phase's dominant role in ultracold hydrogen exchange reactions.

Findings

Geometric phase causes up to four orders of magnitude change in rate coefficients.

The effect is significant across vibrationally resolved and total rate coefficients.

Large geometric phase effects can be exploited to control reactivity.

Abstract

Quantum reactive scattering calculations for the hydrogen exchange reaction H + H$_2$($v=4$, $j=0$) $\to$ H + H$_2$($v'$, $j'$) and its isotopic analogues are reported for ultracold collision energies. Due to the unique properties associated with ultracold collisions, it is shown that the geometric phase effectively controls the reactivity. The rotationally resolved rate coefficients computed with and without the geometric phase are shown to differ by up to four orders of magnitude. The effect is also significant in the vibrationally resolved and total rate coefficients. The dynamical origin of the effect is discussed and the large geometric phase effect reported here might be exploited to control the reactivity through the application of external fields or by the selection of a particular nuclear spin state.