Gibson K D, Sibener S J
The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA.
Phys Chem Chem Phys. 2021 Apr 7;23(13):7902-7907. doi: 10.1039/d0cp05019a. Epub 2020 Dec 21.
In this paper, we examine a new method for isotope separation involving the embedding of atoms and molecules into ice. This method is based upon isotope dependent embedding, i.e. capture, in a cryogenic matrix which exhibits excellent single-pass enrichment as demonstrated successfully for selected isotopes of Xe. This is a totally new method that holds significant promise as a quite general method for enrichment and purification. It is based upon exploiting the energetic and momentum barriers that need to be overcome in order to embed a given isotope or isotopologue into the capture matrix, initially amorphous ice. From our previous experiments, we know that there is a strong dependence of the embedding probability with incident momentum. Using supersonic molecular beam techniques, we generated Xe atomic beams of controlled velocities, relatively narrow velocity distributions due to supersonic expansion, and with all of the entrained isotopes having identical velocities arising from the seeded molecular beam expansion. As we had postulated, the heavier isotope becomes preferentially absorbed, i.e., embedded, in the ice matrix. Herein we demonstrate the efficacy of this method by comparing the capture of Xe and Xe to the reference isotope, Xe. Enrichment of the heavier isotopes in the capture matrix was 1.2 for Xe and 1.3 for Xe greater than that expected for natural abundance. Note that enriched isotopic fractions can be collected from either the condensate or the reflected fraction depending on interest in either the heavier or lighter isotope, respectively. Cycling of these single-step enrichment events for all methods can lead to significantly higher levels of purification, and routes to scale-up can be realistically envisioned. This method holds significant promise to be quite general in applicability, including both atomic isotopes or molecular isotopologues across a wide range of particle masses spanning, essentially, the periodic table. This topic has profound implications and significant potential impact for a wide-variety of isotope-based technologies in the physical and biological sciences, medicine, advanced energy and energetic systems, including isotopically-purified materials that exhibit high-performance electronic and thermal characteristics, as well as isotopically purified spin-free materials for use in quantum information science platforms.
在本文中，我们研究了一种新的同位素分离方法，该方法涉及将原子和分子嵌入冰中。此方法基于同位素依赖嵌入，即在低温基质中捕获，对于选定的Xe同位素已成功证明其具有出色的单级富集效果。这是一种全新的方法，作为一种相当通用的富集和纯化方法具有巨大潜力。它基于利用为了将给定的同位素或同位素分子嵌入捕获基质（最初为非晶冰）中而需要克服的能量和动量势垒。从我们之前的实验可知，嵌入概率强烈依赖于入射动量。利用超音速分子束技术，我们生成了速度可控的Xe原子束，由于超音速膨胀，其速度分布相对较窄，并且所有夹带的同位素因种子分子束膨胀而具有相同的速度。正如我们所假设的，较重的同位素优先被吸收，即嵌入冰基质中。在此，我们通过比较Xe和Xe相对于参考同位素Xe的捕获情况来证明该方法的有效性。捕获基质中较重同位素的富集倍数，Xe为1.2，Xe为1.3，高于自然丰度预期值。注意，根据对较重或较轻同位素的兴趣，富集的同位素组分可分别从冷凝物或反射组分中收集。对所有方法进行这些单步富集过程的循环可导致显著更高的纯化水平，并且可以切实设想扩大规模的途径。该方法在适用性上具有很大的通用性，包括跨越基本上整个周期表的各种粒子质量的原子同位素或分子同位素分子。这个主题对物理和生物科学、医学、先进能源和高能系统中的各种基于同位素的技术具有深远的影响和重大的潜在影响，包括具有高性能电子和热特性的同位素纯化材料，以及用于量子信息科学平台的同位素纯化无自旋材料。
