Ultracold chemistry with alkali-metal-rare-earth molecules

Abstract

A first principles study of the dynamics of ${}^6$Li(${}^2$S) + ${}^6$Li${}^{174}$Yb(${}^2{\Sigma }^{+}$)${\to }^6$Li${}_2{(}^1{\Sigma }^{+}$) + ${}^{174}$Yb(${}^1$S) reaction is presented at cold and ultracold temperatures. The computations involve determination and analytic fitting of a three-dimensional potential energy surface for the Li${}_2$Yb system and quantum dynamics calculations of varying complexities, ranging from exact quantum dynamics within the close-coupling scheme, to statistical quantum treatment, and universal models. It is demonstrated that the two simplified methods yield zero-temperature limiting reaction rate coefficients in reasonable agreement with the full close-coupling calculations. The effect of the three-body term in the interaction potential is explored by comparing quantum dynamics results from a pairwise potential that neglects the three-body term to that derived from the full interaction potential. Inclusion of the three-body term in the close-coupling calculations was found to reduce the limiting rate coefficients by a factor of two. The reaction exoergicity populates vibrational levels as high as $v=19$ of the ${}^6$Li${}_2$ molecule in the limit of zero collision energy. Product vibrational distributions from the close-coupling calculations reveal sensitivity to inclusion of three-body forces in the interaction potential. Overall, the results indicate that a simplified model based on the long-range potential is able to yield reliable values of the total reaction rate coefficient in the ultracold limit but a more rigorous approach based on statistical quantum or quantum close-coupling methods is desirable when product rovibrational distribution is required.

12 pages, 9 figures

References in corpus (4)

• A High Phase-Space-Density Gas of Polar Molecules
• Ultracold dense samples of dipolar RbCs molecules in the rovibrational and hyperfine ground state
• Reactions of ultracold alkali metal dimers
• Ultracold Fermionic Feshbach Molecules of ${}^{23}$Na${}^{40}$K

Cited by in corpus (7)

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• Laser control of ultracold molecule formation: The case of RbSr
• Probing the Efimov discrete scaling in atom-molecule collision
• The Li + CaF $\to$ Ca + LiF chemical reaction under cold conditions
• Multichannel quantum-defect theory for anisotropic interactions
• Non-adiabatic quantum interference effects and chaoticity in the ultracold Li + LiNa $\to$ Li${}_2$ + Na reaction