Control of Ultracold Photodissociation with Magnetic Fields

TL;DR

This paper demonstrates control over ultracold molecular photodissociation using magnetic fields, revealing quantum mechanical effects in fragment distributions and validating a multichannel quantum chemistry model.

Contribution

It introduces a method to manipulate ultracold photodissociation reactions with magnetic fields and confirms theoretical predictions with experimental data.

Findings

Magnetic fields below 10 G significantly alter photofragment angular distributions.

Experimental results agree with multichannel quantum chemistry models including nonadiabatic effects.

Strong mixing of partial waves observed in the photofragment energy continuum.

Abstract

Photodissociation of a molecule produces a spatial distribution of photofragments determined by the molecular structure and the characteristics of the dissociating light. Performing this basic chemical reaction at ultracold temperatures allows its quantum mechanical features to dominate. In this regime, weak applied fields can be used to control the reaction. Here, we photodissociate ultracold diatomic strontium in magnetic fields below 10 G and observe striking changes in photofragment angular distributions. The observations are in excellent qualitative agreement with a multichannel quantum chemistry model that includes nonadiabatic effects and predicts strong mixing of partial waves in the photofragment energy continuum. The experiment is enabled by precise quantum-state control of the molecules.