Optical methods of enantiomeric-specific state transfer had been proposed theoretically based on a cyclic three-level system of chiral molecules. According to these theoretical methods, recently the breakthrough progress has been reported in experiments (Eibenberger etal 2017 Phys. Rev. Lett. 118 123002; Prez etal 2017 Angew. Chem. Int. Ed. 56 12512) for cold gaseous chiral molecules but with achieving low state-specific enantiomeric enrichment. One of the limiting factors is the influence of the thermal population in the selected cyclic three-level system based on purely rotational transitions in the experiments. Here, we theoretically explore the improvement of the enantiomeric-specific state transfer at finite temperature by introducing ro-vibrational transitions for the cyclic three-level system of chiral molecules. Then, at the typical experimental temperature, approximately only the lowest state in the desired cyclic three-level system is thermally occupied and the optical method of enantiomeric-specific state transfer works well. Comparing with the case of purely rotational transitions where all the three states are thermally occupied, this modification will remarkably increase the obtained state-specific enantiomeric enrichment with enantiomeric excess being approximately 100%.

理论上基于手性分子的循环三能级系统，提出了对映体特异性状态转移的光学方法。根据这些理论方法，最近取得突破性进展已在实验中报道（Eibenberger等人2017年物理学快报牧师。 118 123002;佩雷斯等人2017年。。Angew化学国际版 5612512）用于冷气态手性分子，但具有较低的状态特异性对映体富集。限制因素之一是在实验中基于纯旋转跃迁的选定循环三能级系统中的热种群影响。在这里，我们通过引入手性分子的循环三能级系统的振动振动转变，在理论上探索了在有限温度下对映体特定状态转移的改进。然后，在典型的实验温度下，所需的循环三能级系统中大约只有最低的状态被热占据，对映体特异性状态转移的光学方法工作得很好。与纯旋转跃迁的情况相比，这三个状态都被热占据，