Reactions of Atomic Thorium and Uranium Cations with SF 6 Studied by Guided Ion Beam Tandem Mass Spectrometry
Reactions of Atomic Thorium and Uranium Cations with SF 6 Studied by Guided Ion Beam Tandem Mass Spectrometry
复制标题
引导离子束串联质谱法研究钍和铀原子阳离子与SF 6 的反应
DOI：
10.1021/acs.jpca.2c02090
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Armentrout, P.B.
中科院分区：
文献类型：
--
作者：
Bubas, Amanda R.;Iacovino, Anna C.;Armentrout, P.B.
由于氟化钍和氟化铀化合物在核燃料系统中的使用，氟化钍和氟化铀的基础化学仍然是人们感兴趣的领域。在这里，我们研究了钍阳离子与六氟化硫的反应，并重新审视了铀阳离子与六氟化硫的反应。通过使用引导离子束串联质谱，我们探索的反应途径，成为访问远高于热能（E = 0.04 eV）。总的来说，我们发现，Th+和U+反应非常有效地与SF6，接近碰撞极限，在热和升高的能量。在低能量下观察到的主要产物包括Th 1 -3+、UF 1 -4+和SF 1 -4+，所有这些都是在无势垒放热过程中形成的。还观察到SF 5+，尽管该通道的压力依赖性揭示了SF 5+通过次级反应以化学方式形成，能量依赖性表明这是ThF 2+和UF 3+与SF6之间的反应的结果。在较高的能量，两个AnF 3+的产品被观察到衰减到AnF++ F2，和SF 4+和SF 2+表现出吸热功能的横截面。对于这两个系统，SF 4+的上升可以归因于在较高能量下的SF 4+通道的压力依赖性的基础上的AnF+与SF6之间的二次碰撞，SF 2+的上升似乎是由于SF 3+分解为SF 2 ++ F。
The fundamental chemistry of the thorium and uranium fluorides continues to be an area of interest because of the use of thorium and uranium fluoride compounds in nuclear fuel systems. Here, we study the reaction of thorium cations with sulfur hexafluoride for the first time and revisit the reaction of uranium cations with sulfur hexafluoride. By using guided ion beam tandem mass spectrometry, we explore the reaction pathways that become accessible well above thermal energies (E∼ 0.04 eV). Overall, we find that both Th+and U+react very efficiently with SF6, approaching the collision limit at both thermal and elevated energies. The primary products observed at low energies include Th1–3+, UF1–4+, and SF1–4+, all of which are formed in barrierless, exothermic processes. SF5+was also observed, although the pressure dependence of this channel reveals that SF5+forms exothermically through secondary reactions, which the energy dependences suggest result from reactions between ThF2+and UF3+with SF6. At higher energies, both AnF3+products are observed to decay to AnF++ F2, and both SF4+and SF2+exhibit cross sections with endothermic features. For both systems, the rise in SF4+can be attributed to a secondary collision between AnF+with SF6on the basis of the pressure dependence of the SF4+channel at higher energies, and the rise in SF2+appears to result from the decomposition of SF3+to SF2++ F.