KRb Feshbach Resonances: Modeling the interatomic potential

TL;DR

This study observed and characterized 28 heteronuclear Feshbach resonances in a 40K-87Rb mixture, refining the interatomic potential model and enabling accurate predictions for molecule formation and other isotopic combinations.

Contribution

The paper provides a highly refined interatomic potential model for KRb, based on experimental Feshbach resonance data, improving predictions of molecular energy levels and resonances.

Findings

Identified 28 Feshbach resonances in 40K-87Rb mixture.

Refined the interatomic potential model for KRb.

Predicted resonances for other potassium isotopic mixtures.

Abstract

We have observed 28 heteronuclear Feshbach resonances in 10 spin combinations of the hyperfine ground states of a 40K 87Rb mixture. The measurements were performed by observing the loss rates from an atomic mixture at magnetic fields between 0 and 700 G. This data was used to significantly refine an interatomic potential derived from molecular spectroscopy, yielding a highly consistent model of the KRb interaction. Thus, the measured resonances can be assigned to the corresponding molecular states. In addition, this potential allows for an accurate calculation of the energy differences between highly excited levels and the rovibrational ground level. This information is of particular relevance for the formation of deeply bound heteronuclear molecules. Finally, the model is used to predict Feshbach resonances in mixtures of 87Rb combined with 39K or 41K.