Interactions and charge-transfer dynamics of anAl+ion immersed in ultracold Rb and Sr atoms

Abstract

Atomic clocks based on an Al + ion sympathetically cooled by a laser-cooled alkaline-earth ion have achieved unprecedented accuracy. Here, we investigate theoretically interactions and charge transfer dynamics of an Al + ion immersed in an ultracold gas of Rb and Sr atoms. We calculate potential energy curves and transition electric dipole moments for the (Al+Rb) + and (Al+Sr) + ion-atom systems using coupled cluster and multireference configuration interaction methods with scalar relativistic effects included within the small-core energy-consistent pseudopotentials in Rb and Sr atoms. The long-range interaction coefficients are also reported. We use the electronic structure data to investigate cold collisions and charge transfer dynamics. Scattering of an Al + ion with alkali-metal or alkaline-earth-metal atom is governed by one potential energy curve whereas charge transfer can lead to several electronic states mixed by the relativistic spin-orbit coupling. We examine the branching ratios resulting from the interplay of the short-and long-range effects, as well as the prospects for the laser-field control and formation of molecular ions. We propose to employ the atomic clock transition in an Al + ion to monitor ion-atom scattering dynamics via quantum logic spectroscopy. The presented results pave the way for the application of atomic ions other than alkali-metal and alkaline-earth-metal ones in the field of cold hybrid ion-atom experiments.

Quantum-Logic Detection of Chemical Reactions

“…Another work traced molecular association of a single cold molecular ion with room-temperature gas using quantum logic [43]. Other recent proposals suggested to employ variation of quantum logic for coherent manipulation of the molecule using phonon resolved transitions [44], and to study the Al + optical clock transition during its interaction with ultracold atoms [45]. Yet, to our knowledge, quantum logic has never been applied to measure the reaction rate of a single pair of cold reactants whose optical control is inaccessible.…”