4 research outputs found
Accurate theoretical determination of the ionization potentials of CaF, SrF, and BaF
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.Comment: 7 pages, before paper submission (references will be added
additionally
Pinning down electron correlations in RaF via spectroscopy of excited states
We report the spectroscopy of 11 electronic states in the radioactive
molecule radium monofluoride (RaF). The observed excitation energies are
compared with state-of-the-art relativistic Fock-space coupled cluster (FS-RCC)
calculations, which achieve an agreement of >99.71% (within ~8 meV) for all
states. High-order electron correlation and quantum electrodynamics corrections
are found to be important at all energies. Establishing the accuracy of
calculations is an important step towards high-precision studies of these
molecules, which are proposed for sensitive searches of physics beyond the
Standard Model.Comment: Submitted for publicatio
Relativistic Coupled Cluster Calculations with Variational Quantum Electrodynamics Resolve the Discrepancy between Experiment and Theory Concerning the Electron Affinity and Ionization Potential of Gold
The first ionization potential (IP) and electron affinity (EA) of the gold atom have been determined to an unprecedented accuracy using relativistic coupled cluster calculations up to the pentuple excitation level including the Breit and QED contributions. We reach meV accuracy (with respect to the experimental values) by carefully accounting for all individual contributions beyond the standard relativistic coupled cluster approach. Thus, we are able to resolve the long-standing discrepancy between experimental and theoretical IP and EA of gold