Structural, mechanical, thermodynamic, and electronic properties of thorium hydrides from first-principles
Structural, mechanical, thermodynamic, and electronic properties of thorium hydrides from first-principles
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DOI：
10.1016/j.jnucmat.2010.04.009
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发表时间：
2010-01
影响因子：
3.1
通讯作者：
Bao-Tian Wang;Ping Zhang;Hong-Zhou Song;Hongliang Shi;Dafang Li;Weidong Li
中科院分区：
文献类型：
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作者：
Bao-Tian Wang;Ping Zhang;Hong-Zhou Song;Hongliang Shi;Dafang Li;Weidong Li
基于密度泛函理论和广义梯度近似，对氢钍（thh2和Th4H15）的结构、电子、力学和热力学性质进行了第一性原理计算。系统地研究了这些材料的平衡几何形状、态的总密度和偏密度、电荷密度、弹性常数、弹性模量、泊松比和声子色散曲线，并与实验和先前的计算结果进行了比较。结果表明，所计算的平衡结构参数与实验结果吻合较好。所有钍氢化物的Th-H键均表现出弱共价特征，但thh2和th4h15的离子性质因氢浓度不同而不同。发现在thh2中，每个Th原子向H转移的电子约为1.5个，而在th4h15中，每个Th原子向H转移的电子约为2.1个。计算的thh22稳定体心四方相声子谱与实验结果吻合较好。此外，我们还发现萤石相中的硫化氢在力学和动力学上都是不稳定的。
We perform first-principles calculations of the structural, electronic, mechanical, and thermodynamic properties of thorium hydrides (ThH2and Th4H15) based on the density functional theory with generalized gradient approximation. The equilibrium geometries, the total and partial densities of states, charge density, elastic constants, elastic moduli, Poisson’s ratio, and phonon dispersion curves for these materials are systematically investigated and analyzed in comparison with experiments and previous calculations. These results show that our calculated equilibrium structural parameters are well consistent with experiments. The Th–H bonds in all thorium hydrides exhibit weak covalent character, but the ionic properties for ThH2and Th4H15are different due to their different hydrogen concentration. It is found that while in ThH2about 1.5 electrons transfer from each Th atom to H, in Th4H15the charge transfer from each Th atom is around 2.1 electrons. Our calculated phonon spectrum for the stable body-centered tetragonal phase of ThH2accords well with experiments. In addition we show that ThH2in the fluorite phase is mechanically and dynamically unstable.