Ab initio electronic structure of the Sr${}_2^{+}$ molecular ion

Abstract

Molecular ions formed in cold hybrid ion-atom experiments may find interesting applications ranging from precision measurements to controlled chemical reactions. Here, we investigate electronic structure of the Sr${}_2^{+}$ molecular ion, which may be produced by photoassociation of laser-cooled Sr${}^{+}$ ions immersed into an ultracold gas of Sr atoms or by ionization of ultracold Sr${}_2$ molecules. Using \textit{ab initio} electronic structure methods, such as the coupled cluster and configuration interaction ones with small-core relativistic energy-consistent pseudopotentials and large Gaussian basis sets, we calculate potential energy curves for the ground and 41 excited electronic states, and electric dipole transition moments between them. We show that alkaline-earth molecular ions despite of their apparently simple structure with three valence electrons only are challenging for state-of-the-art quantum chemistry methods due to their multireference nature and high density of states. Finally, we calculate and analyze Franck-Condon factors governing the photoionization of ground-state Sr${}_2$ molecules into ${}^2{\Sigma }_u^{+}$ and ${}^2{\Sigma }_g^{+}$ states of Sr${}_2^{+}$ molecular ions. The present results may be useful for studying and guiding formation and spectroscopy of cold Sr${}_2^{+}$ molecular ions.

12 pages, 8 figures, 7 tables

References in corpus (20)

• Cold molecules: Progress in Quantum Engineering of Chemistry and Quantum Matter
• A trapped single ion inside a Bose-Einstein condensate
• Precision Test of Mass Ratio Variations with Lattice-Confined Ultracold Molecules
• Sum-rules and bath-parametrization for quantum cluster theories
• Creation of ultracold Sr2 molecules in the electronic ground state
• Narrow Line Photoassociation in an Optical Lattice
• Spectroscopic accuracy directly from quantum chemistry: application to ground and excited states of beryllium dimer
• Molecular lattice clock with long vibrational coherence
• Cold interactions between an Yb${}^{+}$ ion and a Li atom: Prospects for sympathetic cooling, radiative association, and Feshbach resonances
• Synthesis of mixed hypermetallic oxide BaOCa${}^{+}$ from laser-cooled reagents in an atom-ion hybrid trap
• Long-range vs. short-range effects in cold molecular ion-neutral collisions: Charge exchange of Rb with N${}_2^{+}$ and O${}_2^{+}$
• Rovibrational dynamics of the strontium molecule in the A^1Σ_u^+, c^3Π_u, and a^3Σ_u^+ manifold from state-of-the-art ab initio calculations
• Observation of collisions between cold Li atoms and Yb${}^{+}$ ions
• Fourier-transform spectroscopy of Sr2 and revised ground state potential
• Reactive collisions of trapped anions with ultracold atoms
• Reaction blockading in charged-neutral excited-state chemistry at low collision energy
• Interactions and chemical reactions in ionic alkali-metal and alkaline-earth-metal diatomic $A{B}^{+}$ and triatomic $A_2{B}^{+}$ systems
• Formation of deeply bound ultracold Sr_2 molecules by photoassociation near the ^1S + ^3P_1 intercombination line
• Quantum-defect theory of resonant charge exchange
• Control of Ultracold Photodissociation with Magnetic Fields

Cited by in corpus (2)

• Excited electronic states of Sr${}_2$: ab initio predictions and experimental observation of the $2^1{\Sigma }_u^{+}$ state
• Characterization of the electronic ground state of Mg${}_2^{+}$ by PFI-ZEKE photoelectron spectroscopy