New Insights into the Formation of Hyperstoichiometric Plutonium Oxides

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• 作者：Bingyun Ao ; Ruizhi Qiu ; Haiyan Lu ; Xiaoqiu Ye ; Peng Shi ; Piheng Chen ; Xiaolin Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：January 8, 2015
• 年：2015
• 卷：119
• 期：1
• 页码：101-108
• 全文大小：464K
• ISSN：1932-7455

文摘

Whether PuO₂ could be further oxidized is a very important topic in Pu chemistry. Experiments on its oxidation have not completely demonstrated the existence of higher oxides. Here, the reaction energies of PuO₂ with a series of molecules and their radiation-induced radicals and products are systematically predicted using first-principles calculations. The results show that F₂ can react with PuO₂, indicating the existence of higher-valence Pu in PuO₂-based materials. Moreover, the formations of PuO_2.25, PuO_2.25H_0.25, and PuO_2.5H_0.5 by the reactions of PuO₂ with O^{鈥?/sup> and OH鈥?/sup> radials are exothermic. However, from the reaction energies of the reactions between hyperstoichiometric Pu oxides and two radicals, PuO_2+xH_x, instead of PuO_2+x, are deduced to be the experimentally observed products in the kinetically favorable environments. The widely discussed PuO_2+x act only as the intermediate products. Electronic structures of these hyperstoichiometric Pu oxides also reveal that PuO_2+xH_x are more stable than PuO_2+x.}