Spectroscopic characterization of buffer-gas-cooled lead monofluoride molecules in the B2Σ+(υ' = 0) ← X12Π1/2(υ = 0) transition

Zesen Wang; Renjun Pang; Jie Ma; Qinning Lin; Shunyong Hou; Hailing Wang; Xiaohu Li; Liang Xu; Xingjia Li; Guanglong Chen; Jinjun Liu; Jianping Yin; Tao Yang

doi:10.1016/j.saa.2024.125508

Spectroscopic characterization of buffer-gas-cooled lead monofluoride molecules in the B²Σ⁺(υ' = 0) ← X₁²Π_1/2(υ = 0) transition

Spectrochim Acta A Mol Biomol Spectrosc. 2024 Nov 28:329:125508. doi: 10.1016/j.saa.2024.125508. Online ahead of print.

Authors

Zesen Wang¹, Renjun Pang¹, Jie Ma¹, Qinning Lin¹, Shunyong Hou¹, Hailing Wang¹, Xiaohu Li², Liang Xu³, Xingjia Li⁴, Guanglong Chen⁴, Jinjun Liu⁵, Jianping Yin¹, Tao Yang⁶

Affiliations

¹ State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, PR China.
² Xinjiang Astronomical Observatory, Chinese Academy of Sciences, 150 Science 1 - Street, Urumqi, Xinjiang 830011, PR China; Xinjiang Key Laboratory of Radio Astrophysics, 150 Science 1-Street, Urumqi, Xinjiang 830011, PR China; Key Laboratory of Radio Astronomy and Technology, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing, 100101, PR China.
³ Shanghai Key Lab of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, PR China.
⁴ School of Mathematics, Physics and Statistics, Shanghai University of Engineering Science, Shanghai 201620, PR China.
⁵ Department of Chemistry and Department of Physics, University of Louisville, Louisville, KY 40292, USA. Electronic address: j.liu@louisville.edu.
⁶ State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, PR China; Xinjiang Astronomical Observatory, Chinese Academy of Sciences, 150 Science 1 - Street, Urumqi, Xinjiang 830011, PR China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, PR China. Electronic address: tyang@lps.ecnu.edu.cn.

PMID: 39662191
DOI: 10.1016/j.saa.2024.125508

Abstract

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 B²Σ⁺(υ'=0) ← X₁²Π_1/2(υ = 0) transition, including both direct absorption and laser-induced fluorescence spectroscopy. A highly concentrated beam of PbF molecules is obtained with a central forward velocity of 223 ± 17 m/s, while 81, 66 and 24 hyperfine-structure-resolved spectral lines with a frequency accuracy of 40 MHz have been assigned respectively for ²⁰⁸PbF, ²⁰⁷PbF and ²⁰⁶PbF isotopologues. The hyperfine constants due to the ¹⁹F nucleus (A_∥ and A_⊥) of the B state are reported for the first time, and those of the ²⁰⁷Pb nucleus have been also updated. Such a cryogenic molecular beam of PbF in association with its hyperfine-structure-resolved spectral atlas of the B²Σ⁺(υ'=0) ← X₁²Π_1/2(υ = 0) transition will be essential in developing sensitive detection schemes towards the eEDM measurement.

Keywords: Lead monofluoride (PbF) molecule; buffer-gas cooling (BGC); electron Electric Dipole Moment (eEDM).