# High-Resolution Spectroscopy of {R}ydberg Molecular States of $^{85}${R}b$_2$ Near the $5s+7p$ Asymptote

## TL;DR

This paper reports high-resolution spectroscopy of low-$n$ Rydberg molecular states in $^{85}$Rb$_2$, revealing detailed line structures and setting a lower bound on the autoionization lifetime, advancing understanding of Rydberg molecules at less extreme internuclear distances.

## Contribution

The study provides the first high-resolution measurements of low-$n$ Rydberg molecular states near the $5s+7p$ asymptote in $^{85}$Rb$_2$, with precise modeling and lifetime estimation.

## Key findings

- Detailed line structure observed and modeled.
- Lower bound of $ au > 1.1 imes 10^{-9}$ s on autoionization lifetime.
- Insights into Rydberg molecules at lower principal quantum numbers.

## Abstract

Rydberg molecules, often exemplified by long-range "trilobite" molecules, are a subject of much recent interest at high principal quantum number $n$. States that use the same bonding mechanism can exist at much lower $n$ and less-extreme internuclear separations that are still quite long range. We use a high-resolution pulsed amplifier to study previously-detected transitions to a low-$n$ Rydberg molecular state near the $5s+7p$ asymptote in $^{85}$Rb$_2$. The observed line structure is modeled using precise ground-state positions and a lower bound of $\tau > 1.1 \times 10^{-9}$ s is set on the excited-state autoionization lifetime.