The $d \: ^3 \Pi$ state of LiRb

TL;DR

This study investigates the $d \, ^3\Pi$ state of ultra-cold LiRb molecules, assessing its suitability for state transfer and photoassociation, and provides spectroscopic data including potential well depth and spin-orbit splitting.

Contribution

The paper provides the first spectroscopic characterization of the $d \, ^3\Pi$ state of LiRb and evaluates its potential for molecular state transfer and photoassociation applications.

Findings

Identified vibrational levels suitable for STIRAP transfer.

Measured the well depth and spin-orbit splitting of the state.

Suggested pathways for short-range photoassociation.

Abstract

We report our spectroscopic studies of the $d \ ^3\Pi$ state of ultra-cold $^7$Li$^{85}$Rb using resonantly-enhanced multi-photon ionization and depletion spectroscopy with bound-to-bound transitions originating from the metastable $a \ ^3\Sigma^+$ state. We evaluate the potential of this state for use as the intermediate state in a STIRAP transfer scheme from triplet Feshbach LiRb molecules to the $X \ ^1\Sigma^+$ ground state, and find that the lowest several vibrational levels possess the requisite overlap with initial and final states, as well as convenient energies. Using depletion measurements, we measured the well depth and spin-orbit splitting. We suggest possible pathways for short-range photoassociation using deeply-bound vibrational levels of this electronic state.