Accurate theoretical determination of the ionization potentials of CaF, SrF, and BaF

TL;DR

This paper provides highly accurate theoretical calculations of the ionization potentials of CaF, SrF, and BaF molecules using advanced relativistic coupled cluster methods, including corrections for higher order effects and QED contributions.

Contribution

It introduces a comprehensive relativistic coupled cluster approach with corrections for higher excitations and QED effects to accurately predict ionization potentials of MF molecules.

Findings

Predictions for CaF and BaF agree with experimental data.

New accurate ionization potential prediction for SrF, suggesting further experiments.

Extensive analysis of computational parameter effects on results.

Abstract

We present a comprehensive theoretical study of the ionization potentials of the MF (M= Ca, Sr, Ba) molecules using the state-of-the-art relativistic coupled cluster approach with single, double, and perturbative triple excitations (CCSD(T)). We have further corrected our results for the higher order excitations (up to full triples) and the QED self energy and vacuum polarisation contributions. We have performed an extensive investigation of the effect of the various computational parameters on the calculated ionisation potentials, which allowed us to assign realistic uncertainties on our predictions. For CaF and BaF, where precise experiments are available, our predictions are in excellent agreement with the measured values. In case of SrF, we provide a new accurate prediction of the ionisation potential that deviates from the available experimental data, motivating further experimental investigations.