Ultracold, radiative charge transfer in hybrid Yb ion - Rb atom traps

Abstract

Ultracold hybrid ion-atom traps offer the possibility of microscopic manipulation of quantum coherences in the gas using the ion as a probe. However, inelastic processes, particularly charge transfer can be a significant process of ion loss and has been measured experimentally for the Yb${}^{+}$ ion immersed in a Rb vapour. We use first-principles quantum chemistry codes to obtain the potential energy curves and dipole moments for the lowest-lying energy states of this complex. Calculations for the radiative decay processes cross sections and rate coefficients are presented for the total decay processes. Comparing the semi-classical Langevin approximation with the quantum approach, we find it provides a very good estimate of the background at higher energies. The results demonstrate that radiative decay mechanisms are important over the energy and temperature region considered. In fact, the Langevin process of ion-atom collisions dominates cold ion-atom collisions. For spin dependent processes \cite{kohl13} the anisotropic magnetic dipole-dipole interaction and the second-order spin-orbit coupling can play important roles, inducing couplingbetween the spin and the orbital motion. They measured the spin-relaxing collision rate to be approximately 5 orders of magnitude higher than the charge-exchange collision rate \cite{kohl13}. Regarding the measured radiative charge transfer collision rate, we find that our calculation is in very good agreement with experiment and with previous calculations. Nonetheless, we find no broad resonances features that might underly a strong isotope effect. In conclusion, we find, in agreement with previous theory that the isotope anomaly observed in experiment remains an open question.

7 figures, 1 table accepted for publication in J. Phys. B: At. Mol. Opt. Phys. arXiv admin note: text overlap with arXiv:1107.1141

References in corpus (8)

• A trapped single ion inside a Bose-Einstein condensate
• Controlling chemical reactions of a single particle
• Quantum theory of ultracold atom-ion collisions
• Cold heteronuclear atom-ion collisions
• Controlled collisions of a single atom and ion guided by movable trapping potentials
• Determination of the 5d6s 3D1 state lifetime and blackbody radiation clock shift in Yb
• Sympathetic cooling of the Ba${}^{+}$ ion by collisions with ultracold Rb atoms: theoretical prospects
• Experimental constraints on the polarizabilities of the 6s^2 1S0 and 6s6p 3P0 states of Yb

Cited by in corpus (5)

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• Radiative charge transfer in collisions of C with He+
• Cold collisions between alkali and alkaline-earth hetero nuclear atom-ion system Li + Ba${}^{+}$
• Cold atom-ion systems in radiofrequency multipole traps: event-drive molecular dynamics and stochastic simulations