2018/06/22 by Alessio Ciamei, Jacek Szczepkowski, Alex Bayerle +9
Physics and Astronomy · #physics.atom-ph #physics.chem-ph
paper · pdf · doi:10.1039/c8cp03919d
published as Phys. Chem. Chem. Phys. 20, 26221 (2018) · 24 pages, 13 figures, 10 tables
arxiv created 2018/06/22 · arxiv updated 2019/07/10
We report on spectroscopic studies of hot and ultracold RbSr molecules, and combine the results in an analysis that allows us to fit a potential energy curve (PEC) for the X(1)2Σ+ ground state bridging the short-to-long-range domains. The ultracold RbSr molecules are created in a μK sample of Rb and Sr atoms and probed by two-colour photoassociation spectroscopy. The data yield the long-range dispersion coefficients C6 and C8, along with the total number of supported bound levels. The hot RbSr molecules are created in a 1000 K gas mixture of Rb and Sr in a heat-pipe oven and probed by thermoluminescence and laser-induced fluorescence spectroscopy. We compare the hot molecule data with spectra we simulated using previously published PECs determined by three different ab-initio theoretical methods. We identify several band heads corresponding to radiative decay from the B(2)2Σ+ state to the deepest bound levels of X(1)2Σ+. We determine a mass-scaled high-precision model for X(1)2Σ+ by fitting all data using a single fit procedure. The corresponding PEC is consistent with all data, thus spanning short-to-long internuclear distances and bridging an energy gap of about 75% of the potential well depth, still uncharted by any experiment. We benchmark ab-initio PECs against our results, and give the PEC fit parameters for both X(1)2Σ+ and B(2)2Σ+ states. As first outcomes of our analysis, we calculate the s-wave scattering properties for all stable isotopic combinations and corroborate the locations of Fano-Feshbach resonances between alkali Rb and closed-shell Sr atoms recently observed [Barbé et al., Nat. Phys., 2018, DOI:10.1038/s41567-018-0169-x]. These results should greatly contribute to the generation of ultracold alkali-alkaline-earth dimers, whose applications range from quantum simulation to quantum chemistry.