Accurate ab initio calculations of adiabatic energy and dipole moment: Prospects for the formation of cold Alkaline-Earth-Francium molecular ions ALKE-Fr⁺ (ALKE = Be, Mg, Ca, and Sr)

Abstract

Alkaline-earth and alkali-metal mixtures have an electronic structure that is perfect for laser cooling. This makes them highly attractive for trapping and laser cooling experiments, allowing the formation of cold molecules. For this object, potential-energy curves and relevant spectroscopic parameters of the low-lying electronic excited states of 1,3Σ+, 1,3Π, and 1,3Δ symmetries of molecular-ion systems composed of alkaline-earth-ion and Francium alkali-metal-atom: ALKE-Fr+ (ALKE = Be, Mg, Ca and Sr), are determined using advanced theoretical technique in quantum chemistry, including a non-empirical pseudopotential, core-valence correlation, large Gaussian basis sets and Full Configuration Interaction (FCI). In order to obtain a more accurate understanding of the electronic structure of these systems, we also determined transition and permanent dipole moments and vibrational properties. Thereafter, the spontaneous and the black-body stimulated transition rates were determined and were employed to calculate lifetimes for all vibrational states of the ground electronic states 11Σ+ of molecular-ions under consideration. For the first and the second excited states, radiative lifetimes were investigated via the Franck–Condon approximation including bound-bound and bound-free transitions. High diagonal structure and large Franck Condon Factor (FCF) values f 00 = 0.987, f 11 = 0.959 and f 22 = 0.919 were obtained for the 11Π (v′ = 0, 1, 2)→ 11Σ+ (v = 0, 1, 2) transition making the BeFr+ system a good candidate for laser cooling. Furthermore, the current results could be used to investigate elastic scattering properties in cold-ion-atom collisions for the first excited states and may help the experimentalists for possible formation, spectroscopy, and photoassociation of cold ion-atom mixtures.

Theoretical Modeling of Sr(q+) He (q = 0, 1, 2) van der Waals Systems Including Spin–Orbit Coupling

“…The vibrational energy level spacing ( E υ+1 – E υ ) for the ground states (X 1 ∑ + and X 2 ∑ + ) of Sr 2+ He and Sr + He, as well as those of their excited states, have been determined both without and with spin–orbit coupling using the Numerov algorithm. − They are presented in Tables and . We remark that the ground state of the Sr 2+ He system presents more vibrational levels than Sr + He, which can be explained by the difference in the well depths.…”

Spectroscopic properties and laser cooling feasibility with the X1∏21/2↔X2∏23/2 transition for the PbX (X = F, Cl, Br, and I) molecules

“…Bigagli et al [27] built a cycling scheme for Doppler cooling of trapped OH + ions using X 3 Σ − ↔ A 3 Π transition. The BeFr + molecule was reported as a good candidate for laser cooling by Zrafi et al [28]. Moreover, a four-laser optical scheme of laser cooling was constructed for the AuAl molecule by Zhu et al [29].…”