Empirical LiK excited state potentials: connecting short range and near dissociation expansions

TL;DR

This paper presents an empirical model of LiK molecule excited state potentials by combining spectroscopic data with long-range theory, aiding the identification of states suitable for coherent transfer to the ground state.

Contribution

It introduces a comprehensive empirical representation of the LiK B^1Π potential connecting short- and long-range data, facilitating molecular state control for dipolar gases.

Findings

Determined transition frequencies for 26 vibrational states.

Extracted C6 dispersion coefficients from combined data.

Identified a vibrational level suitable for coherent transfer.

Abstract

We report on a high-resolution spectroscopic survey of ${}^{6}\textrm{Li}{}^{40}\textrm{K}$ molecules near the $2\textrm{S}+4\textrm{P}$ dissociation threshold and produce a fully empirical representation for the $\textrm{B}^{1}\Pi$ potential by connecting available short- and long-range data. The purpose is to identify a suitable intermediate state for a coherent Raman transfer to the absolute ground state, and the creation of a molecular gas with dipolar interactions. Starting from weakly bound ultracold Feshbach molecules, the transition frequencies to twenty-six vibrational states are determined. Our data are combined with long-range measurements [Ridinger et al., EPL, 2011, 96, 33001], and near-dissociation expansions for the spin-orbit coupled potentials are fitted to extract the $C_6$ dispersion coefficients. A suitable vibrational level is identified by resolving its Zeeman structure and by comparing the experimentally attained g-factor to our theoretical prediction. Using mass-scaling of the short-range data for the $\textrm{B}^{1}\Pi$ [Pashov et al., Chem. Phys. Lett., 1998, 292, 615-620] and an updated value for its depth, we model the short- and the long-range data simultaneously and produce a Rydberg-Klein-Rees curve covering the entire range.