Prospects for assembling ultracold radioactive molecules from laser-cooled atoms
Jacek Klos, Hui Li, Eite Tiesinga, Svetlana Kotochigova
Molecules with unstable isotopes often contain heavy and deformed nuclei and thus possess a high sensitivity to parity-violating effects, such as Schiff moments. Currently the best limits on Schiff moments are set with diamagnetic atoms. Polar molecules with quantum-enhanced sensing capabilities, however, can offer better sensitivity. In this work, we consider the prototypical $^223}$Fr$^107}$Ag molecule, as the octupole deformation of the unstable $^223}$Fr francium nucleus amplifies the nuclear Schiff moment of the molecule by two orders of magnitude relative to that of spherical nuclei and as the silver atom has a large electronegativity. To develop a competitive experimental platform based on molecular quantum systems, $^223}$Fr atoms and $^107}$Ag atoms have to be brought together at ultracold temperatures. That is, we explore the prospects of forming $^223}$Fr$^107}$Ag from laser-cooled Fr and Ag atoms. We have performed fully relativistic electronic-structure calculations of ground and excited states of FrAg that account for the strong spin-dependent relativistic effects of Fr and the strong ionic bond to Ag. In addition, we predict the nearest-neighbor densities of magnetic-field Feshbach resonances in ultracold $^223}$Fr+$^107}$Ag collisions with coupled-channel calculations. These resonances can be used for magneto-association into ultracold, weakly-bound FrAg. We also determine the conditions for creating $^223}$Fr$^107}$Ag molecules in their absolute ground state from these weakly-bound dimers via stimulated Raman adiabatic passage using our calculations of the relativistic transition electronic dipole moments.
, Li, H.
, Tiesinga, E.
and Kotochigova, S.
Prospects for assembling ultracold radioactive molecules from laser-cooled atoms, New Journal of Physics, [online], https://doi.org/10.1088/1367-2630/ac50ea, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933895
(Accessed June 7, 2023)