Candidates for direct laser cooling of diatomic molecules with the simplest Σ1−Σ1 electron

Abstract

We propose to utilize the 1 Σ-1 Σ electronic transition system for direct laser cooling of heteronuclear diatomic molecules. AgH, as well as its deuterium isotopologue AgD, is used as an example to illustrate the cooling schemes. Potential energy curves and relevant molecular parameters of both AgH and AgD, including the spin-orbit constants and the electronic transition dipole moments, are determined in internally contracted multiconfiguration-reference configuration interaction calculations. The highly diagonal Franck-Condon matrices of the A 1 Σ +-X 1 Σ + transitions predicted by the calculations suggest the existence of quasi-closed-cycle transitions, which renders these molecules suitable for direct laser cooling. By solving rate equations numerically, we demonstrated that both AgH and AgD molecules can be cooled from 25 K to 2 mK temperature in approximately 20 milliseconds. Our investigation elucidates and supports the hypothesis that molecules in the simplest 1 Σ-1 Σ system can serve as favorable candidates for direct laser cooling.

Two Cycling Centers in One Molecule: Communication by Through-Bond Interactions and Entanglement of the Unpaired Electrons

“…Diagonal FCFs can be realized in molecules in which a single unpaired electron is localized at the cycling center (often, an alkaline-earth metal, a rare-earth metal, or a lanthanide), giving rise to atom-like transitions. Several molecules in this class have been experimentally laser-cooled to (sub)­millikelvin temperatures, − and many more have been proposed on the basis of electronic structure calculations. − Particularly noteworthy are breakthroughs by Doyle’s group, who succeeded in laser-cooling SrOH and, more recently, YbOH, opening possibilities for the cooling of even larger polyatomic molecules with various cycling centers. , The ability to laser-cool polyatomic molecules is crucial for progress in this domain: for example, symmetric-top molecules offer new opportunities in the field of quantum computing and precision measurements …”

Electronic structure of ground and low-lying excited states of BaLi+ molecular ion: spin-orbit effect, radiative lifetimes and Franck-Condon factor

“…We conclude that the overlap of vibrational wave functions between these states is insufficient to achieve direct laser cooling for BaLi + ionic molecule. The laser cooling processes for Alkali and Alkaline earth molecules are investigated previously [57][58][59][60][61].…”

Electronic excited states of monobromosilylene molecules including the spin–orbit-coupling

“…To date, little information is available for the electronic excited states beyond the A 1 A′′ state of HSiBr. In addition, relativistic effects including the spin–orbit-coupling (SOC) effect, which is expected to have a significant influence on the behavior of the electronic states in compounds containing heavy atoms, 28–30 have not been investigated for HSiBr yet. To this end, we perform here a theoretical study using the internally contracted multireference configuration interaction (icMRCI-F12) with Davidson correction to investigate the electronic excited states of HSiBr.…”