氯化铊的激光冷却：理论研究。

Laser cooling of thallium chloride: A theoretical investigation.

机构信息

Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China and Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, Changchun 130012, China.

Department of Physics, National University of Defense Technology, Changsha 410073, China.

出版信息

J Chem Phys. 2018 Sep 7;149(9):094306. doi: 10.1063/1.5044387.

DOI:10.1063/1.5044387

PMID:30195288

Abstract

The possibility of laser cooling of thallium chloride (TlCl) molecules has been investigated based on high-level calculations with the consideration of the core-valence and the spin-orbit coupling (SOC) effects. The potential energy curves of the 13 Λ-S states as well as the 24 Ω states split from them via SOC are obtained by multi-reference configuration interaction plus the Davidson correction. We show that the a transition of TlCl is a possible candidate for laser cooling, which features highly diagonal Franck-Condon factors and no intermediate interacting electronic states. Based on our calculations, we propose an optical cycling scheme by utilizing four lasers at wavelengths around 320 nm with more than 10 cycles for photon absorption/emission and a sub-microkelvin temperature limit.

摘要

已经基于考虑了芯-价和自旋-轨道耦合（SOC）效应的高精度计算，研究了氯化铊（TlCl）分子激光冷却的可能性。通过多参考组态相互作用加上戴维森修正，获得了 13 Λ-S 态以及通过 SOC 分裂出来的 24 Ω 态的势能曲线。我们表明，TlCl 的 a 跃迁是激光冷却的一个可能的候选者，其具有高度对角的 Franck-Condon 因子，并且没有中间相互作用的电子态。基于我们的计算，我们提出了一种光学循环方案，利用四个波长约为 320nm 的激光，通过超过 10 个光子吸收/发射循环，实现亚微开尔文温度极限。