New Insights into the Crystal Structures of Plutonium Hydrides from First-Principles Calculations
New Insights into the Crystal Structures of Plutonium Hydrides from First-Principles Calculations
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从第一性原理计算对氢化钚晶体结构的新见解
DOI：
10.1021/acs.jpcc.7b11464
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发表时间：
2018-05-10
影响因子：
3.7
通讯作者：
Gao, Tao
中科院分区：
文献类型：
--
作者：
Li, Shichang;Ao, Bingyun;Gao, Tao
钚氢腐蚀的重要研究内容之一是确定钚氢化物的复杂晶体结构和钚与氢的键合相互作用。然而，由于钚氢化物的高活性、高毒性和放射性，进行结构表征是非常困难的。本文采用密度泛函理论+ U方法研究了环境压力下钚氢化物的晶体结构、晶格振动和键合特性。结果表明，PuH3具有多种竞争相结构。综合考虑自旋极化、强相关(U)和自旋轨道耦合对总能量和晶格动力学稳定性的影响，发现在环境压力下PuH3更可能是六边形P6(3)cm或三角形P3c1结构，而不是通常假设的六边形P6(3)/mmc （laf3型）和面心立方（bif3型）结构。计算的电子结构清楚地表明P6(3)cm (P3c1) PuH3是一种带隙较小的半导体，带隙约为0.87 eV （0.85 eV）。Pu氢化物中的Pu- h键主要受离子相互作用的支配。
One of the important research contents on hydrogen corrosion of plutonium is the determination of the complex crystal structures of plutonium hydrides and the bonding interactions between plutonium and hydrogen. However, it is very difficult to carry out the structural characterization of plutonium hydrides because of their high activity, high toxicity, and radioactivity. In this work, the crystal structures, lattice vibrations, and bonding properties of plutonium hydrides under ambient pressure are investigated by means of the density functional theory + U approach. Results show that PuH3 exhibits many competition phase structures. After considering spin polarization, strong correlation (U), and spinorbit coupling effects on the total energy and lattice dynamics stability, it is found that PuH3 at ambient pressure is more likely to be hexagonal P6(3)cm or trigonal P3c1 structure, instead of the usual supposed structures of hexagonal P6(3)/mmc (LaF3-type) and face-centered cubic (BiF3-type). The calculated electronic structures clearly indicate that P6(3)cm (P3c1) PuH3 is a semiconductor with a small band gap about 0.87 eV (0.85 eV). The Pu-H bonds in Pu hydrides are dominated by the ionic interactions.