The electronic system (2)2Σ+ and (1)2Π of LiCa

Abstract

High-resolution Fourier transform spectroscopy and Laser-induced fluorescence have been performed on LiCa in the infrared spectral range. We analyse rovibrational transitions of the $(2{)}^2{\mathrm{\Sigma }}^{+}$–$X(1{)}^2{\mathrm{\Sigma }}^{+}$ system of LiCa and find the $(2{)}^2{\mathrm{\Sigma }}^{+}$ state to be perturbed by spin–orbit coupling to the $(1{)}^2\mathrm{\Pi }$ state. We study the coupled system obtaining molecular parameters for the $(2{)}^2{\mathrm{\Sigma }}^{+}$ and the $(1{)}^2\mathrm{\Pi }$ 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 $(2{)}^2{\mathrm{\Sigma }}^{+}$. An improved analytic potential function of the $X(1{)}^2{\mathrm{\Sigma }}^{+}$ state is derived, due to the extension of the observed rotational ladder.

GRAPHICAL ABSTRACT

Keywords:

• PACS 31.50.-x Potential energy surfaces
• PACS 33.15.Mt Rotation
• vibration
• and vibration–rotation constants
• PACS 33.20.-t Molecular spectra

Acknowledgments

We submit this article in honor of Wim Ubachs on the occasion of his 65${}^{th}$ birthday. We thank Horst Knöckel and Asen Pashov for many helpful discussions and advice during the course of this research.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Notes

1 spin-rotation splitting, see Section 3