Lifetimes of ultralong-range Rydberg molecules in vibrational ground and excited state

TL;DR

This study experimentally investigates the lifetimes of ultralong-range Rydberg molecules in different vibrational states, revealing density-dependent decay and the impact of quantum reflection on molecular stability.

Contribution

It provides new experimental data on molecular lifetimes and introduces a classical scattering model to explain density effects and state-dependent lifetime reductions.

Findings

Molecular lifetimes depend on ground state atom density.

Excited molecular states have shorter lifetimes than ground states.

Quantum reflection influences molecular stability and lifetime.

Abstract

Since their first experimental observation, ultralong-range Rydberg molecules consisting of a highly excited Rydberg atom and a ground state atom have attracted the interest in the field of ultracold chemistry. Especially the intriguing properties like size, polarizability and type of binding they inherit from the Rydberg atom are of interest. An open question in the field is the reduced lifetime of the molecules compared to the corresponding atomic Rydberg states. In this letter we present an experimental study on the lifetimes of the ^3\Sigma (5s-35s) molecule in its vibrational ground state and in an excited state. We show that the lifetimes depends on the density of ground state atoms and that this can be described in the frame of a classical scattering between the molecules and ground state atoms. We also find that the excited molecular state has an even more reduced lifetime compared to the ground state which can be attributed to an inward penetration of the bound atomic pair due to imperfect quantum reflection that takes place in the special shape of the molecular potential.