α-Pu和δ-Pu电子结构的密度泛函理论计算

发布时间：2018-04-16 01:22

本文选题：α-Pu + δ-Pu　；参考：《原子能科学技术》2017年04期

【摘要】：采用密度泛函理论框架下的平面波赝势方法,对α-Pu和δ-Pu的电子结构进行了对比研究。由电荷布居分析可知,α-Pu中8种位置的原子的轨道电荷分布各不相同,净电荷的得失主要由s和p电子贡献,而δ-Pu中各原子的轨道电荷分布一致,且无净电荷的得失;由态密度可知,α-Pu的态密度主峰较δ-Pu的态密度主峰峰值更低、宽度更宽,表明α-Pu中平均键能强于δ-Pu,导致其更难发生塑性形变。此外,α-Pu电子的能量总体上低于δ-Pu电子的,这也是α-Pu的室温稳定性高于δ-Pu的重要原因。α-Pu中8种不同位置Pu原子的分波态密度的计算结果表明,8号位置Pu原子的5f电子关联性最强,对α-Pu的自旋矩贡献最大,而1号位置Pu原子的5f电子关联性最弱,对自旋矩的贡献最小;由电荷密度图可知,δ-Pu的电子云为均匀的球形,无明显的相互作用,呈现典型的金属键特征,而α-Pu的电子云发生重叠,相互作用明显,具有共价行为,这也在一定程度上揭示了两者呈现不同延脆性机制。
[Abstract]:The electronic structures of 伪 -Pu and 未 -Pu are studied by using the plane wave pseudopotential method under the framework of density functional theory.From the analysis of charge distribution, it can be seen that the orbital charge distribution of the eight atoms in 伪 -Pu is different, and the gain and loss of net charge are mainly contributed by s and p electrons, while the orbital charge distribution of each atom in 未 -Pu is the same, and the gain and loss of net charge are not the same.The density of states of 伪 -Pu is lower and wider than that of 未 -Pu, which indicates that the average bond energy in 伪 -Pu is stronger than that in 未 -Pu.In addition, the energy of 伪 -Pu electrons is generally lower than that of 未 -Pu electrons, which is the important reason that the stability of 伪 -Pu at room temperature is higher than that of 未 -Pu.The contribution to the spin moment of 伪 -Pu is the largest, while the 5f electron correlation of the Pu atom at position 1 is the weakest, and the contribution to the spin moment is the least, and the electron cloud of 未 -Pu is a uniform sphere with no obvious interaction from the charge-density diagram.The electronic cloud of 伪 -Pu has overlapping, obvious interaction and covalent behavior, which to some extent reveals the different mechanism of ductility between 伪 -Pu and 伪 -Pu.
【作者单位】：火箭军工程大学;中国科学院力学研究所高温气体动力学国家重点实验室;
【基金】：国家自然科学基金资助项目(11472280)
【分类号】：O641.1

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