1 research outputs found
High accuracy theoretical investigations of CaF, SrF, and BaF and implications for laser-cooling
The NL-eEDM collaboration is building an experimental setup to search for the
permanent electric dipole moment of the electron in a slow beam of cold barium
fluoride molecules [Eur. Phys. J. D, 72, 197 (2018)]. Knowledge of molecular
properties of BaF is thus needed to plan the measurements and in particular to
determine an optimal laser-cooling scheme. Accurate and reliable theoretical
predictions of these properties require incorporation of both high-order
correlation and relativistic effects in the calculations. In this work
theoretical investigations of the ground and the lowest excited states of BaF
and its lighter homologues, CaF and SrF, are carried out in the framework of
the relativistic Fock-space coupled cluster (FSCC) and multireference
configuration interaction (MRCI) methods. Using the calculated molecular
properties, we determine the Franck-Condon factors (FCFs) for the transition, which was successfully used for
cooling CaF and SrF and is now considered for BaF. For all three species, the
FCFs are found to be highly diagonal. Calculations are also performed for the
transition recently
exploited for laser-cooling of CaF; it is shown that this transition is not
suitable for laser-cooling of BaF, due to the non-diagonal nature of the FCFs
in this system. Special attention is given to the properties of the
state, which in the case of BaF causes a leak channel, in contrast
to CaF and SrF species where this state is energetically above the excited
states used in laser-cooling. We also present the dipole moments of the ground
and the excited states of the three molecules and the transition dipole moments
(TDMs) between the different states.Comment: Minor changes; The following article has been submitted to the
Journal of Chemical Physics. After it is published, it will be found at
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