Associative ionization in a dilute ultracold $^7$Li gas probed with a hybrid trap

TL;DR

This study investigates associative ionization in ultracold lithium gases using a hybrid trap, revealing ion formation dynamics and long-lived molecular ions under laser illumination.

Contribution

It provides new insights into ionization processes and molecular dynamics in ultracold gases, highlighting the role of laser fields and collision-induced ion formation.

Findings

Li$_2^+$ ions are formed during ultracold collisions.

Li$_2^+$ ions can be long-lived despite MOT laser exposure.

Rapid conversion of Li$_2^+$ to Li$^+$ occurs without MOT light.

Abstract

The formation of Li$_2^+$ and subsequently Li$^+$ ions, during the excitation of $^7$Li atoms to the $3S_{1/2}$ state in a $^7$Li magneto optical trap (MOT), is probed in an ion-atom hybrid trap. Associative ionization occurs during the collision of Li($2P_{3/2}$) and Li($3S_{1/2}$) ultracold atoms, creating Li$_2^+$ ions. Photodissociation of Li$_2^+$ by the MOT lasers is an active channel for the conversion of Li$_2^+$ to Li$^+$. A fraction of the Li$_2^+$ ions is long lived even in the presence of MOT light. Additionally, rapid formation of Li$^+$ from Li$_2^+$ in the absence of MOT light is observed. Resonant excitation of ultracold atoms, resulting in intricate molecular dynamics, reveals important processes in ultracold dilute gases.