The electronic system $(2)^2\Sigma^+$ and $(1)^2\Pi$ of LiCa

TL;DR

This study investigates the electronic states of LiCa using high-resolution spectroscopy, revealing spin-orbit coupling effects and providing improved molecular potential functions for the involved states.

Contribution

It provides detailed molecular parameters and potential functions for the coupled $(2)^2\Sigma^+$ and $(1)^2\Pi$ states of LiCa, including the effects of spin-orbit coupling.

Findings

Identification of perturbation between states due to spin-orbit coupling.

Determination of molecular parameters for coupled states.

Development of an improved analytic potential for the $X(1)^2\Sigma^+$ state.

Abstract

High resolution Fourier transform spectroscopy and Laser induced fluorescence has been performed on LiCa in the infrared spectral range. We analyze rovibrational transitions of the $(2)^2\Sigma^+$--$X(1)^2\Sigma^+$ system of LiCa and find the $(2)^2\Sigma^+$ state to be perturbed by spin-orbit coupling to the $(1)^2\Pi$ state. We study the coupled system obtaining molecular parameters for the $(2)^2\Sigma^+$ and the $(1)^2\Pi$ state together with effective spin-orbit and spin-rotation coupling constants. The coupled system has also been evaluated by applying a potential function instead of rovibrational molecular parameters for the state $(2)^2\Sigma^+$. An improved analytic potential function of the $X(1)^2\Sigma^+$ state is derived, due to the extension of the observed rotational ladder.