Anomalies in the rotational spectra of $^{86}$Sr ULRRM dimers

TL;DR

This study investigates unusual rotational spectral anomalies in $^{86}$Sr ultralong-range Rydberg molecules, revealing behavior unique to $^{86}$Sr triplet dimers and suggesting possible links to scattering lengths or angular momentum exchange.

Contribution

First detailed analysis of rotational anomalies in $^{86}$Sr ULRRMs, highlighting their unique behavior compared to other isotopes and states.

Findings

Anomalies are sensitive to intermediate state detuning.

Behavior is specific to $^{86}$Sr triplet dimers.

No similar anomalies observed in other isotopic or spin states.

Abstract

Anomalies in the rotational structure of $^{86}$Sr $^3S_1$ dimer ultralong-range Rydberg molecules (ULRRMs) created in a cold strontium gas by two-photon excitation via the intermediate $5s5p~^3P_1$ state are reported. Measurements reveal that the distribution of product rotational states is sensitive to intermediate state detuning. Comparative studies using $^{84}$Sr $^1S_0$ and $^3S_1$, and $^{86}$Sr $^1S_0$ dimers display no similar behavior, indicating that the observed behavior is peculiar to $^{86}$Sr triplet dimers. While we have no definitive hypothesis as to the physical mechanism responsible for this behavior, possible explanations might involve the very different scattering lengths for $^{84}$Sr and $^{86}$Sr, or the interchange of spin and rotational angular momentum.