Anomalies in the rotational spectra of ⁸⁶Sr ultralong-range Rydberg molecule dimers

Abstract

Anomalies in the rotational structure of ⁸⁶Sr ³𝑆₁ dimer ultralong-range Rydberg molecules created in a cold strontium gas by two-photon excitation via the intermediate 5⁢𝑠⁢5⁢𝑝 ³𝑃₁ state are reported. Measurements reveal that the distribution of product rotational states is sensitive to intermediate state detuning. Comparative studies using ⁸⁴Sr ¹𝑆₀ and ³𝑆₁, and ⁸⁶Sr ¹𝑆₀ dimers display no similar behavior, indicating that the observed behavior is peculiar to ⁸⁶Sr 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 ⁸⁴Sr and ⁸⁶Sr, or the interchange of spin and rotational angular momentum.