Single-Ion Recycling Reactions
Single-Ion Recycling Reactions
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DOI：
10.1002/anie.201203550
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发表时间：
2012-01-01
影响因子：
16.6
通讯作者：
Drewsen, Michael
中科院分区：
文献类型：
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作者：
Hansen, Anders K.;Sorensen, Magnus A.;Drewsen, Michael
在过去的十年里，涉及共振冷却分子离子的气相化学取得了巨大的进展。[1-14]这包括单分子的实验，[3-6，11]除了有可能提供比整体实验更详细的信息外，还可能是某些类型实验的要求。例如，为了进入超冷化学的新分支，[2，7]超冷离子化学，其中在微开尔文范围内的温度下预期新颖的量子效应，[14，15]需要对单个或最多几个离子进行直接或交感边带激光冷却[16]。此外，对于这一领域的反应实验，一种能够再生单个目标离子的实验方法对于避免射频阱中重新加载所造成的有害的过度微动[5，6]将是极其有价值的。目标离子的再生对于稀有物种的化学研究也是至关重要的，例如transactinide离子的重要情况，即，原子序数为Z！104.由于反式锕系元素的电子结构中存在强烈的相对论效应，这些离子的化学性质特别有趣。[17]虽然反锕系元素的一些化学性质已经被表征，直到哥白尼（Z= 112），[18]这些元素的详细化学仍然是巨大的未探索的，因为它们的生产率极低（通常每天检测到几个或更少）在世界上只有少数加速器设施。目前生产的反式锕系元素同位素（268 Db）的半衰期长达32小时[19]，而且“稳定岛”[20]就在眼前，然而，一个全新的化学领域将触手可及，只要有一种技术允许重复使用单个靶离子。在此，我们报告的回收反应，其中相同的两个激光冷却和捕获的稀有同位素48 Ca+离子（48 Ca天然丰度：0.189%）与HD（83%）和H2（17%）分子的气体混合物反复反应，通过再生的48 Ca+离子通过光解离由短激光脉冲每次形成的分子离子。从总共87个记录的单离子反应事件中，发现48 CaD+分子离子形成的分数为0.56 × 0.05。此外，总反应速率
In the past decade, there has been a tremendous progress in gas-phase chemistry involving sympathetically cooled molecular ions.[1–14] This includes experiments with single molecules,[3–6, 11] which besides having the potential to provide more detailed information than obtainable in experiments with ensembles, can be a requirement for certain types of experiments. For instance, to enter the new branch of ultracold chemistry,[2, 7] ultracold ion chemistry, where novel quantum effects are expected at temperatures in the microkelvin range,[14, 15] direct or sympathetic sideband laser cooling [16] of a single or, at most, a few ions are required. In addition, for reaction experiments in this regime, an experimental method by which a single target ion can be regenerated would be extremely valuable to avoid detrimental excess micromotion [5, 6] inflicted by reloading in radio frequency traps.Regeneration of a target ion would furthermore be vital for chemical studies of rare species, such as the important case of transactinide ions, that is, ions of elements with atomic numbers Z! 104. Because of strong relativistic effects in the electron structure of the transactinides, the chemical properties of these ions are especially intriguing.[17] Though some chemical properties of transactinide elements up to copernicium (Z= 112) have been characterized,[18] the detailed chemistry of these elements is still vastly unexplored because of their extremely low production rates (typically a few detected per day or less) at only a few accelerator facilities worldwide. With half-lives of up to 32h for currently produced transactinide isotopes (268Db),[19] and with the “island of stability”[20] in sight, a whole new realm of chemistry would, however, be within reach, provided a technique allowing repeated use of a single target ion. Herein, we report for the first time on recycling reactions in which the same two laser-cooled and trapped rare isotope 48Ca+ ions (48Ca natural abundance: 0.189%) reacted repeatedly with a gas mixture of HD (83%) and H2 (17%) molecules by regenerating the 48Ca+ ion through photodissociation by a short laser pulse each time a molecular ion was formed. From the total of 87 recorded single-ion reaction events, the fractional 48CaD+ molecular ion formation was found to be 0.56 Æ 0.05. Furthermore, a total reaction rate