Vibrational branching ratios and hyperfine structure of ${}^{11}$BH and its suitability for laser cooling

Abstract

The simple structure of the BH molecule makes it an excellent candidate for direct laser cooling. We measure the branching ratios for the decay of the ${\mathrm{A}}^1\Pi (v^{\prime }=0)$ state to vibrational levels of the ground state, ${\mathrm{X}}^1{\Sigma }^{+}$, and find that they are exceedingly favourable for laser cooling. We verify that the branching ratio for the spin-forbidden transition to the intermediate ${\mathrm{a}}^3\Pi$ state is inconsequentially small. We measure the frequency of the lowest rotational transition of the X state, and the hyperfine structure in the relevant levels of both the X and A states, and determine the nuclear electric quadrupole and magnetic dipole coupling constants. Our results show that, with a relatively simple laser cooling scheme, a Zeeman slower and magneto-optical trap can be used to cool, slow and trap BH molecules.

arXiv comment7 pages, 5 figures. Updated analysis of A state hyperfine structure and other minor revisions

References in corpus (9)

• Cold and Ultracold Molecules: Science, Technology, and Applications
• Laser cooling of a diatomic molecule
• Magneto-optical trapping of a diatomic molecule
• Magneto-optical trapping of diatomic molecules
• Destabilization of dark states and optical spectroscopy in Zeeman-degenerate atomic systems
• Laser radiation pressure slowing of a molecular beam
• Design for a fountain of YbF molecules to measure the electron's electric dipole moment
• Cold and Slow Molecular Beam
• Microwave spectroscopy of Lambda-doublet transitions in the ground state of CH