Global analysis of data on the spin-orbit coupled $A^{1}\Sigma_{u}^{+}$ and $b^{3}\Pi_{u}$ states of Cs2

TL;DR

This paper combines experimental data from multiple sources to derive potential curves and spin-orbit interaction functions for the perturbed A^{1}\Sigma_{u}^{+} and b^{3}\Pi_{u} states of Cs2, advancing understanding of their electronic structure.

Contribution

It provides a comprehensive analysis of Cs2's excited states using diverse experimental data and advanced computational methods, including fitted spin-orbit functions and ab initio comparisons.

Findings

Derived potential curves for Cs2 states.

Fitted spin-orbit interaction functions.

Comparison with ab initio calculations.

Abstract

We present experimentally derived potential curves and spin-orbit interaction functions for the strongly perturbed $A^{1}\Sigma_{u}^{+}$ and $b^{3}\Pi_{u}$ states of the cesium dimer. The results are based on data from several sources. Laser-induced fluorescence Fourier transform spectroscopy (LIF FTS) was used some time ago in the Laboratoire Aim\'{e} Cotton primarily to study the $X ^{1}\Sigma_{g}^{+}$ state. More recent work at Tsinghua University provides information from moderate resolution spectroscopy on the lowest levels of the $b^{3}\Pi_{0u}^{\pm}$ states as well as additional high resolution data. From Innsbruck University, we have precision data obtained with cold Cs$_{2}$ molecules. Recent data from Temple University was obtained using the optical-optical double resonance polarization spectroscopy technique, and finally, a group at the University of Latvia has added additional LIF FTS data. In the Hamiltonian matrix, we have used analytic potentials (the Expanded Morse Oscillator form) with both finite-difference (FD) coupled-channels and discrete variable representation (DVR) calculations of the term values. Fitted diagonal and off-diagonal spin-orbit functions are obtained and compared with {\it ab initio} results from Temple and Moscow State universities.