Measurement of the molecular dipole moment and the hyperfine and Λ -doublet splittings of the BΠ13 state of thallium fluoride

Abstract

We report high-precision measurements on the thallium fluoride 𝐽 ̃ = 1 hyperfine manifold of the B 3 1 (v = 0) state. The measurements are made by monitoring the fluorescence induced by laser excitation of a cryogenic molecular beam. This state is of special interest because it is central to an optical cycling scheme that is envisioned to play an important role in enhancing the sensitivity of the proposed CeNTREX nuclear Schiff-moment experiment presently under construction. We present a novel acousto-optic modulator coincident resonance technique which has allowed a more precise determination of the 𝐽 ̃ = 1 manifold of hyperfine level splittings. We observe Stark shifts of the 𝐽 ̃ = 1 levels and infer a permanent electric dipole moment of 2.28(7) D and -doublet splittings for the F1 = 1/2 and F1 = 3/2 manifolds of 14.4(9) MHz and 17.4(11) MHz, respectively.

Reassessing the potential of TlCl for laser cooling experiments via four-component correlated electronic structure calculations

“…In comparison to the experiment, the PDM measurements of the a 3 Π 1 state of TlF by Clayburn et al, 10 which yielded a value of −2.28(7) D, are in very good agreement with our MRCI 4Z (−2.46 D) or CBS (−2.47 D) results, as well as our EOM-CCSD 3Z results (−2.47 D). From that, and the very similar MRCI and CCSD results for TlCl, we expect that our calculations do provide a good estimate of the experimental value.…”

“…Hunter et al 9 proposed the use of spin-forbidden transition a 3 Π 1 -X 1 Σ + 0 to set up cooling optical cycling for TlF, leading different groups to investigate its spectroscopic properties experimentally. 10,11 More recently, the CeNTREX collaboration 12 has been conducting experiments with 205 TlF molecular beams.…”