Molecular ion trap-depletion spectroscopy of BaCl$^+$

TL;DR

This paper introduces a straightforward method for molecular ion spectroscopy using trap loss detection, providing the first spectroscopic data for BaCl$^+$ and advancing toward ultracold molecular ions.

Contribution

It presents a novel trap-loss spectroscopy technique for BaCl$^+$ ions, enabling accurate molecular potential determination and spectroscopic constants measurement.

Findings

First spectroscopic data for BaCl$^+$ obtained.

Excellent agreement between experimental and theoretical photodissociation cross-sections.

Method paves the way for ultracold molecular ion production.

Abstract

We demonstrate a simple technique for molecular ion spectroscopy. BaCl$^+$ molecular ions are trapped in a linear Paul trap in the presence of a room-temperature He buffer gas and photodissociated by driving an electronic transition from the ground X$^1\Sigma^+$ state to the repulsive wall of the A$^1\Pi$ state. The photodissociation spectrum is recorded by monitoring the induced trap loss of BaCl$^+$ ions as a function of excitation wavelength. Accurate molecular potentials and spectroscopic constants are determined. Comparison of the theoretical photodissociation cross-sections with the measurement shows excellent agreement. This study represents the first spectroscopic data for BaCl$^+$ and an important step towards the production of ultracold ground-state molecular ions.