Towards a spectroscopically accurate set of potentials for heavy hydride laser cooling candidates: effective core potential calculations of BaH

Abstract

BaH (and its isotopomers) is an attractive molecular candidate for laser cooling to ultracold temperatures and a potential precursor for the production of ultracold gases of hydrogen and deuterium. The theoretical challenge is to simulate the laser cooling cycle as reliably as possible and this paper addresses the generation of a highly accurate ab initio ${}^2{\Sigma }^{+}$ potential for such studies. The performance of various basis sets within the multi-reference configuration-interaction (MRCI) approximation with the Davidson correction (MRCI+Q) is tested and taken to the complete basis set limit. It is shown that the calculated molecular constants using a 46 electron Effective Core-Potential (ECP), the augmented polarized core-valence quintuplet basis set (aug-pCV5Z-PP) but only including three active electrons in the MRCI calculation are in close agreement with the available experimental values. The predicted dissociation energy D${}_e$ for the X${}^2{\Sigma }^{+}$ state (extrapolated to the complete basis set (CBS) limit) is 16895.12 cm${}^{-1}$ (2.094 eV), which agrees within 0.1$\%$ of a revised experimental value of $<$16910.6 cm${}^{-1}$, while the calculated r${}_e$ is within 0.03 pm of the experimental result.

arXiv comment14 pages, 9 figures: final accepted version

References in corpus (10)

• Theory and applications of atomic and ionic polarizabilities
• Comment on: "Estimating the Hartree-Fock limit from finite basis set calculations" [Jensen F (2005) Theor Chem Acc 113:267]
• Electric dipole polarizabilities at imaginary frequencies for the alkali-metal, alkaline-earth, and inert gas atoms
• Lorentz and CPT tests with hydrogen, antihydrogen, and related systems
• Ultracold hydrogen and deuterium production via Doppler-cooled Feshbach molecules
• Relativistic coupled cluster calculations of spectroscopic and chemical properties for element 120
• BaH molecular spectroscopy with relevance to laser cooling
• High resolution photoassociation spectroscopy of the ${}^6$Li${}_2$ $1^3{\Sigma }_g^{+}$ state
• On the accuracy of the optical determination of the proton charge radius
• Beryllium monohydride (BeH): Where we are now, after 86 years of spectroscopy

Cited by in corpus (2)

• Assignment of excited-state bond lengths using branching-ratio measurements: The B${}^2{\Sigma }^{+}$ state of BaH molecules
• Combining Slater-type orbitals and effective core potentials