Phase Diagram and Bonding States of Pu−H Binary Compounds at High Pressures
Phase Diagram and Bonding States of Pu−H Binary Compounds at High Pressures
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Pu·H 二元化合物在高压下的相图和键合状态
DOI：
10.1021/acs.jpcc.9b11550
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Xiaoqiu Ye
中科院分区：
文献类型：
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作者：
Jinghong Zhao;Bingyun Ao;Shichang Li;Tao Gao;Xiaoqiu Ye
The high-pressure processes of plutonium hydrides are usually involved in many practical situations, such as the volume expansion during the hydride formation, the pressure of helium bubbles due to the decay of plutonium, and the stress due to the formation of the oxide film. These cases could lead to the high-pressure phase transition of plutonium hydrides and thereby affect the properties of the material. The crystal structure and bonding properties of plutonium hydrides (PuH1–10) under atmospheric pressure and high pressure are investigated by using the first-principle method in combination with a structure searching technique. Our results show that the predicted lattice structures of plutonium hydrides are stable over the given pressure range. A novel stable stoichiometry, PuH with space groupFm3̅m, is thermodynamically, dynamically, and mechanically stable in the pressure range of 62–188 GPa, which may be synthesized through the pressure-induced disproportionation of PuH2. In particular, our theoretically predicted results indicate that PuH3undergoes pressure-induced phase transitions with the following sequence of phases,P63cm→Pnma→R3̅m→Cmcm, and the corresponding transition pressures are computed to be 4, 76, and 150 GPa, respectively. Interestingly, the most striking feature of PuH3is the pressure-induced transition from insulating to metallic forms. Analysis of the electric structures, charge density differences, and electronic localization functions indicates that all phases act mainly as metallic with ionic bonding at high pressure.
