Experimental and theoretical study of the B(2)$^2 \Sigma^+ \rightarrow$ X(1)$^2 \Sigma^+$ system in the KSr molecule

TL;DR

This study combines experimental spectroscopy and advanced electronic structure calculations to analyze the B(2)$^2 \\Sigma^+ \rightarrow$ X(1)$^2 \\Sigma^+$ transition in KSr, providing fundamental constants to aid ultracold molecule research.

Contribution

It presents the first combined experimental and theoretical analysis of the KSr molecule's electronic transition, deriving spectroscopic constants with high accuracy.

Findings

Spectral bands recorded using thermoluminescence technique.

Spectra simulated with three advanced electronic structure methods.

Fundamental spectroscopic constants derived for ground and excited states.

Abstract

Spectral bands for the B(2)$^{2}\Sigma^{+}\rightarrow$ X(1)$^{2}\Sigma^{+}$ electronic transition in the doubly-polar open-shell KSr molecule are recorded at moderate resolution using the thermoluminescence technique. The spectra are simulated using three kinds of advanced electronic structure calculations, allowing for an assessment of their accuracy on one hand, and for the derivation of fundamental spectroscopic constants of the X(1)$^{2}\Sigma^{+}$ KSr ground state and the excited electronic state B(2)$^{2}\Sigma^{+}$, on the other hand. These results should facilitate further studies aiming at creating ultracold bosonic or fermionic KSr molecules.