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

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, and 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 higher-order excitations (up to full triples) and the QED self-energy and vacuum-polarization contributions. We have performed an extensive investigation of the effect of the various computational parameters on the calculated ionization potentials, which allowed us to assign realistic uncertainties to our predictions. For CaF and BaF, where precise experimental measurements are available, our predictions are in excellent agreement with the measured values. In the case of SrF, we provide a theoretical prediction of the ionization potential that deviates from the available experimental measurements, motivating further experimental investigations.</p

Local photoionization feedback effects on galaxies

We implement an optically thin approximation for the effects of the local radiation field from stars and hot gas on the gas heating and cooling in the N-body SPH code GASOLINE2. We resimulate three galaxies from the NIHAO project: one dwarf, one Milky Way-like and one massive spiral, and study what are the local radiation field effects on various galaxy properties. We also study the effects of varying the Ultra Violet Background (UVB) model, by running the same galaxies with two different UVBs. Galaxy properties at z = 0 like stellar mass, stellar effective mass radius, HI mass, and radial extent of the HI disc, show significant changes between the models with and without the local radiation field, and smaller differences between the two UVB models. The intrinsic effect of the local radiation field through cosmic time is to increase the equilibrium temperature at the interface between the galaxies and their circumgalactic media (CGM), moving this boundary inwards, while leaving relatively unchanged the gas inflow rate. Consequently, the temperature of the inflow increases when considering the local radiation sources. This temperature increase is a function of total galaxy mass, with a median CGM temperature difference of one order of magnitude for the massive spiral. The local radiation field suppresses the stellar mass growth by 20 per cent by z = 0 for all three galaxies, while the HI mass is roughly halfed. The differences in the gas phase diagrams, significantly impact the HI column densities, shifting their peaks in the distributions towards lower NHI

Local photoionization feedback effects on galaxies

We implement an optically thin approximation for the effects of the local radiation field from stars and hot gas on the gas heating and cooling in the N-body smoothed particle hydrodynamics code gasoline2. We resimulate three galaxies from the NIHAO project: one dwarf, one Milky Way-like, and one massive spiral, and study what are the local radiation field effects on various galaxy properties. We also study the effects of varying the ultraviolet background (UVB) model, by running the same galaxies with two different UVBs. Galaxy properties at z = 0 like stellar mass, stellar effective mass radius, H i mass, and radial extent of the H i disc show significant changes between the models with and without the local radiation field, and smaller differences between the two UVB models. The intrinsic effect of the local radiation field through cosmic time is to increase the equilibrium temperature at the interface between the galaxies and their circumgalactic media (CGM), moving this boundary inwards, while leaving relatively unchanged the gas inflow rate. Consequently, the temperature of the inflow increases when considering the local radiation sources. This temperature increase is a function of total galaxy mass, with a median CGM temperature difference of one order of magnitude for the massive spiral. The local radiation field suppresses the stellar mass growth by 20 per cent by z = 0 for all three galaxies, while the H i mass is roughly halved. The differences in the gas phase diagrams, significantly impact the H i column densities, shifting their peaks in the distributions towards lower NH i