Enantio-conversion with the help of electromagnetic fields is an essential issue due to the chirality dependence of many chemical, biological, and pharmaceutical processes. Here, we propose a method for this issue based on a five-level double-$\mathrm{\Delta }$ model of chiral molecules. By utilizing the breaking of left-right symmetry in two $\mathrm{\Delta }$-type substructures, we can establish chiral-state-selective excitations with one chiral ground state being excited to an achiral excited state and the other one being undisturbed. In the meanwhile, the achiral excited state will relax to two chiral ground states. The two effects simultaneously acting on chiral mixtures can convert molecules of different chiralities to ones of the same chirality, i.e., enantio-conversion via optical pumping. We numerically show that highly efficient enantio-conversion can be achieved. Our method works in the appearance of decoherences and without the precise control of pulse durations (pulse areas) or pulse shapes. These advantages offer it promising features in promoting the future exploration of enantio-conversion.

中文翻译：

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通过光泵浦进行手性混合物的对映转换

由于许多化学，生物和制药过程的手性依赖性，借助电磁场进行对映体转化是一个必不可少的问题。在此，我们针对此问题提出了一种基于五级双$\mathrm{\Delta }$手性分子模型。通过利用左右对称在两个方面的破坏$\mathrm{\Delta }$式子结构，我们可以建立手性态选择性激发，其中一个手性基态被激发为非手性激发态，另一个未被扰动。同时，非手性激发态将松弛到两个手性基态。同时作用于手性混合物的两种效应可以将不同手性的分子转化为相同手性的分子，即通过光泵浦进行对映体转化。我们用数值方法表明可以实现高效的对映转换。我们的方法工作在退相干的外观上，并且无法精确控制脉冲持续时间（脉冲区域）或脉冲形状。这些优点为促进未来对映体转化的探索提供了有希望的特征。