Ortho-Parapositronium Quenching by Paramagnetic Molecules and Ions
Ortho-Parapositronium Quenching by Paramagnetic Molecules and Ions
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顺磁性分子和离子的正位电子淬灭
DOI：
10.1103/physrev.110.1355
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发表时间：
1958
期刊：
影响因子：
--
通讯作者：
R. A. Ferrell
中科院分区：
文献类型：
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作者：
R. A. Ferrell
顺磁性分子如NO对正电子偶素长寿命的猝灭通常被解释为由于正电子偶素电子与分子中单个奇数未配对电子交换而导致的自旋翻转。这个概念被重新审视，它被发现，自旋翻转实际上是无关紧要的，淬火的唯一必要条件是交换可能与一个或多个未成对电子。另一个例子是由O 2分子引起的众所周知的强猝灭，其两个未成对电子可以在有和没有自旋翻转的情况下进行交换。此外，还简要讨论了顺磁离子在水溶液中的猝灭作用。进一步指出，在苯中二苯基苦基肼（DPH）对正电子偶素的猝灭，通常被认为是交换猝灭的一个主要例子，可能是完全不同的起源。有证据表明，这种淬火更可能是由于一个简单的捕获的正电子素原子的DPH分子。
The quenching of the long lifetime of orthopositronium by a paramagnetic molecule such as NO is generally interpreted as due to a spin flip resulting from exchange of the positronium electron with the single odd unpaired electron of the molecule. This concept is re-examined and it is found that spin flip is actually irrelevant, the only essential condition for quenching being that exchange be possible with one or more unpaired electrons. A further example is the well-known strong quenching caused by the O 2 molecule, whose two unpaired electrons can undergo exchange both with and without spin flip. In addition the quenching by paramagnetic ions in aqueous solution is briefly discussed. It is further noted that the quenching of orthopositronium by diphenylpicrylhydrazyl (DPH) in benzene, generally regarded as a prime example of exchange quenching, is probably of quite different origin. Evidence is presented that this quenching is more likely due to a simple capture of the positronium atom by the DPH molecule.