High resolution spectroscopy of B0u+←X0g+ transitions in 130Te2: Reference lines spanning the 443.2-451.4 nm region.

Molecular tellurium (130Te2) has long been regarded as a promising candidate for a variety of spectroscopic applications, especially as a frequency reference. Absorption lines of 130Te2 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 130Te2 Doppler-free saturated absorption transitions is reported, and used to assign multiple ro-vibrational bands in the B(Σu-3)0u+←X(Σu-3)0g+ electronic transition via the Dunham model, giving updated Dunham parameters and diatomic constants for the B(Σu-3)0u+ state at an unprecedented level of precision. Our findings reveal spectroscopic properties of 130Te2 that might eventually contribute to frequency reference in precision measurement such as the quest for non-zero electron's Electric Dipole Moment (eEDM).

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

Alkaline-earth-metal monohydrides MH (M = 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 A2Π1/2 ← X2Σ+ 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 X2Σ+, the transition wavelengths in the vacuum, and hyperfine branching ratios of A2Π1/2(J' = 1/2,+) ← X2Σ+(N = 1,-), followed by possible sideband modulation proposals to address all hyperfine manifolds. Lastly, the Zeeman energy level structures and associated magnetic g factors of the ground state X2Σ+(N = 1,-) were also presented. Our theoretical results here not only shed more light on the molecular spectroscopy of alkaline-earth-metal monohydrides toward laser cooling and magneto-optical trapping but also can contribute to research in molecular collisions involving few-atom molecular systems, spectral analysis in astrophysics and astrochemistry, and even precision measurement of fundamental constants such as the quest for nonzero detection of electron's electric dipole moment.

High resolution spectroscopic measurement of 130Te2: Reference lines near 444.4 nm for eEDM experiment using PbF molecules.

Molecular tellurium (Te2) offers a wide range of potential applications, including frequency reference. Spectroscopic results about the 130Te2 spectrum were previously reported, but few lines lie around the PbF transition of A (2Σ+) (υ' = 0) â† X12Π1/2 (υ = 0) (∼444.4 nm) which is regarded as an eEDM (electron's Electric Dipole Moment) sensitive transition. Here electronic transition lines for 130Te2 were determined using the Saturated Absorption Spectroscopy method, where the origin of the transition band was investigated for the B1 (3Σu-)0u+ (υ' = 10) â† X1 (3Σg-)0g+ (υ = 5) transition. The Dunham model with high orders was utilized to assign these transition lines, while Dunham parameters of the excited state B1 (υ' = 10) were updated to a new level. The Toptica TA-SHG Pro laser was then locked to a single absorption line using a P-I servo. Our results here not only provide the assigned atlas of Te2 spectrum near 444.4 nm, but also contribute to a stable and sensitive spectroscopic detection of PbF molecules toward the eEDM measurement, which is significant in understanding the fundamental physics beyond the Standard Model.