Spectroscopic characterization of buffer-gas-cooled lead monofluoride molecules in the BΣ(υ' = 0) ← XΠ(υ = 0) transition.

Establishing a nonzero measurement of the electron Electric Dipole Moment (eEDM) has long been a fundamental pursuit in atomic, molecular and optical physics, offering possible insights into new physics beyond the Standard Model. In this regard, lead monofluoride (PbF) has emerged as a potential candidate for measuring eEDM primarily due to its suitable properties such as the strong internal effective electric field, and eEDM-sensitive ground state with large Ω-doubling and small magnetic g factor. In the present work, we realized the production of a buffer-gas-cooled PbF molecular beam and characterized its high-resolution spectroscopy in the BΣ(υ'=0) ← XΠ(υ = 0) transition, including both direct absorption and laser-induced fluorescence spectroscopy.

High resolution spectroscopy of B0←X0 transitions in Te: Reference lines spanning the 443.2-451.4 nm region.

Molecular tellurium (Te) has long been regarded as a promising candidate for a variety of spectroscopic applications, especially as a frequency reference. Absorption lines of Te were published extensively in the past few decades, however, the spectral resolution was not sufficiently high to be considered a precision spectroscopic reference. Here, a high resolution spectral atlas of Te Doppler-free saturated absorption transitions is reported, and used to assign multiple ro-vibrational bands in the B(Σu-3)0←X(Σu-3)0 electronic transition via the Dunham model, giving updated Dunham parameters and diatomic constants for the B(Σu-3)0 state at an unprecedented level of precision.

Theoretical Investigation of Spectroscopic Properties of the Alkaline-Earth-Metal Monohydrides toward Laser Cooling and Magneto-Optical Trapping.

Alkaline-earth-metal monohydrides H ( = Be, Mg, Ca, Sr, Ba) have long been regarded as promising candidates toward laser cooling and trapping; however, their rich internal level structures that are amenable to magneto-optical trapping have not been completely explored. Here, we first systematically evaluated Franck-Condon factors of these alkaline-earth-metal monohydrides in the Π ← Σ transition, exploiting three respective methods (the Morse potential, the closed-form approximation, and the Rydberg-Klein-Rees method). The effective Hamiltonian matrix was introduced for MgH, CaH, SrH, and BaH individually in order to figure out their molecular hyperfine structures of Σ, the transition wavelengths in the vacuum, and hyperfine branching ratios of Π(' = 1/2,+) ← Σ( = 1,-), followed by possible sideband modulation proposals to address all hyperfine manifolds.

High resolution spectroscopic measurement of Te: Reference lines near 444.4 nm for eEDM experiment using PbF molecules.

Molecular tellurium (Te) offers a wide range of potential applications, including frequency reference. Spectroscopic results about the Te spectrum were previously reported, but few lines lie around the PbF transition of A (Σ) (υ' = 0) ← XΠ (υ = 0) (∼444.4 nm) which is regarded as an eEDM (electron's Electric Dipole Moment) sensitive transition.