Four-component full relativistic study on the spectroscopic properties and direct laser cooling schemes for the PbH, PoH, BiH+, and AtH+ molecules

• Published in: Journal of quantitative spectroscopy & radiative transfer Vol. 321; p. 109001
• Main Authors: Luan, Jing-Zhen, Yang, Chuan-Lu, Li, Xiao-Hu, Zhao, Wen-Kai, Liu, Yu-Liang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2024
• Subjects: ab initio calculation; Frank-Condon factor; Laser cooling; Relativistic; Spin-orbit coupling; Spin-orbit coupling; Relativistic; ab initio calculation; Laser cooling; Frank-Condon factor
• ISSN: 0022-4073; 1879-1352
• DOI: 10.1016/j.jqsrt.2024.109001

•Laser cooling schemes are built for the PbH, PoH, BiH+, and AtH+ molecules.•SOC splitting states are used for the closed transitions with high diagonal FCFs.•Accurate PECs are obtained using KRCI based on four-component relativistic orbitals.•The spectroscopic parameters correspond to the available experimental data. The pseudo-closed transition with enough large Frank-Condon factor (FCF) is a necessary condition for direct laser cooling molecules, which means that only a few molecules with the appropriate ground and excited electronic states can be considered as potential candidates. The electronic and spectroscopic properties of five Ω states are evaluated for the PbH, PoH, BiH+, and AtH+ molecules based on the four-component full relativistic calculations with all-electron basis sets, by which we construct optical schemes for these molecules by using the X12Π1/2 (ν'') ↔ X22Π3/2 (ν') transitions for PbH and BiH+ or the X12Π3/2 (ν'') ↔ X22Π1/2 (ν') ones for PoH and AtH+. The built schemes can provide 104 ∼ 105 scattering phonons with three or five pumping lasers. Moreover, the Doppler/recoil temperatures are 2.08 × 10−3/0.04, 2.91 × 10−3/0.11, 7.48 × 10−3/0.08 and 0.01/0.18 μK, respectively, which means that the temperature of the order of nanokelvin for the PbH and PoH and microkelvin for the BiH+ and AtH+ molecules may be cooled based on the present optical schemes. [Display omitted]