The $C \: ^1 \Sigma ^+$, $A \: ^1 \Sigma ^+$, and $b \: ^3 \Pi_{0^+}$ states of LiRb

TL;DR

This study reports the first spectroscopic observations of specific electronic states in LiRb molecules, providing detailed vibrational data and laying groundwork for future research in molecular physics.

Contribution

First spectroscopic characterization of the $C \, ^1\Sigma^+$, $A \, ^1\Sigma^+$, and $b \, ^3\Pi_{0^+}$ states in LiRb, including vibrational constants and energy levels.

Findings

Observed multiple vibrational levels of the $C \, ^1\Sigma^+$ state.

Mapped vibrational levels of the $A \, ^1\Sigma^+$ - $b \, ^3\Pi_{0^+}$ complex.

Determined term energies and vibrational constants for all studied states.

Abstract

We present the first spectroscopic studies of the $C \ ^1\Sigma^+$ electronic state and the $A \ ^1\Sigma^+$ - $b \ ^3\Pi_{0^+}$ complex in $^7$Li - $^{85}$Rb. Using resonantly-enhanced, two-photon ionization, we observed $v = 7$, 9, 12, 13 and $26-44$ of the $C \ ^1\Sigma^+$ state. We augment the REMPI data with a form of depletion spectra in regions of dense spectral lines. The $A \ ^1\Sigma^+$ - $b \ ^3\Pi_{0^+}$ complex was observed with depletion spectroscopy, depleting to vibrational levels $v=0 \rightarrow 29$ of the $A \ ^1\Sigma^+$ state and $v=8 \rightarrow 18$ of the $b \ ^3\Pi_{0^+}$ state. For all three series, we determine the term energy and vibrational constants. Finally, we outline several possible future projects based on the data presented here.