57 research outputs found
Cold interactions and chemical reactions of linear polyatomic anions with alkali-metal and alkaline-earth-metal atoms
We consider collisional studies of linear polyatomic ions immersed in
ultracold atomic gases and investigate the intermolecular interactions and
chemical reactions of several molecular anions (,
, , ,
) with alkali-metal (Li, Na, K, Rb, Cs) and
alkaline-earth-metal (Mg, Ca, Sr, Ba) atoms. State-of-the-art ab initio
techniques are applied to compute the potential energy surfaces (PESs) for
these systems. The coupled cluster method restricted to single, double, and
noniterative triple excitations, CCSD(T), is employed and the scalar
relativistic effects in heavier metal atoms are modeled within the small-core
energy-consistent pseudopotentials. The leading long-range isotropic and
anisotropic induction and dispersion interaction coefficients are obtained
within the perturbation theory. The PESs are characterized in detail and their
universal similarities typical for systems dominated by the induction
interaction are discussed. The two-dimensional PESs are provided for selected
systems and can be employed in scattering calculations. The possible channels
of chemical reactions and their control are analyzed based on the energetics of
reactants. The present study of the electronic structure is the first step
towards the evaluation of prospects for sympathetic cooling and controlled
chemistry of linear polyatomic ions with ultracold atoms.Comment: 12 pages, 4 figures, 3 table
Energetics and control of ultracold isotope-exchange reactions between heteronuclear dimers in external fields
We show that isotope-exchange reactions between ground-state alkali-metal,
alkaline-earth-metal, and lanthanide heteronuclear dimers consisting of two
isotopes of the same atom are exothermic with an energy change in the range of
1-8000MHz thus resulting in cold or ultracold products. For these chemical
reactions there are only one rovibrational and at most several hyperfine
possible product states. The number and energetics of open and closed reactive
channels can be controlled by the laser and magnetic fields. We suggest a
laser-induced isotope- and state-selective Stark shift control to tune the
exothermic isotope-exchange reactions to become endothermic thus providing the
ground for testing models of the chemical reactivity. The present proposal
opens the way for studying the state-to-state dynamics of ultracold chemical
reactions beyond the universal limit with a meaningful control over the quantum
states of both reactants and products.Comment: 5 pages, 1 figure, 1 tabl
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