A theoretical explanation of RbBH4's fractionally occupied ground-state phase and the reorientational motion of the [BH4](-) group
文献类型：期刊论文
| 作者 | Chen, Lei; Song, Qi; Zhou, Bo; Zhang, Xiaodong; Jiang, Zhenyi |
| 刊名 | JOURNAL OF PHYSICS D-APPLIED PHYSICS
 |
| 出版日期 | 2017-11-15 |
| 卷号 | 50页码:12 |
| 关键词 | first-principles calculations fractional occupied ground-state phase hydrogen storage alkaline metal borohydrides |
| ISSN号 | 0022-3727 |
| DOI | 10.1088/1361-6463/aa86f7 |
| 英文摘要 | In this work, a pseudo-structure model is adopted to describe the fractionally occupied phase of RbBH4 at low temperatures. The fractionally occupied cubic ground state with Fm3m symmetry can be explained as a superposition and average of three well-defined pseudo-structures with P43m, F43m and P4(2)/nmc symmetries. First, both mechanical and dynamical stability of these pseudo-structures are supported by the calculated elastic constants and phonon spectra, respectively. By comparing the electronic structure, elastic properties and thermodynamic properties of these well-defined pseudo-structures, it can be found that all pseudo-structures exhibit a certain degree of similarity. Second, the system is stabilized by charge transfer. Bader charge analysis of the pseudo-structures shows that charge transfer in RbBH4 contributes a constant shift in formation energy. Coulomb interaction energy and total electronic energy variations with the unit cell volume have been obtained. The results show that the larger the volume of the unit cell, the lower the difference of Coulomb interaction energy between the pseudo-structures P43m, F43m and P4(2)/nmc. Third, the barrier energies calculated for paths of transitions between these pseudo-structures vary significantly with the volume. As the cell volume decreases from 512 to 216 angstrom(3), the B-H covalent bonds are compressed from 1.242 to 1.208 angstrom. Meanwhile, the rotational barrier of [BH4](-) anion increases rapidly, from 0.04 to 0.97 eV. Last, considering the temperature effect, the free energy and entropy contributions are calculated based on the rigid rotor harmonic oscillator approximation. The Gibbs free energy shows that at low temperature the P42/nmc structure is the preferred structure, and with increasing temperature, the P43m structure becomes the preferred structure. We found that the fractionally occupied phase of RbBH4 can be explained by the size of the Rb+ cation and a subtle balance between the Coulomb interaction energy, electronic total energy and thermal vibration energy. |
| WOS关键词 | TOTAL-ENERGY CALCULATIONS ; AUGMENTED-WAVE METHOD ; ALKALI BOROHYDRIDES ; HYDROGEN-STORAGE ; MBH4 M ; ELECTRON-GAS ; BASIS-SET ; DIFFRACTION ; DYNAMICS ; CS |
| 资助项目 | Natural Science Foundation of Shaanxi Provincial Department of Education[17JK0782] |
| WOS研究方向 | Physics |
| 语种 | 英语 |
| WOS记录号 | WOS:000413107100001 |
| 出版者 | IOP PUBLISHING LTD |
| 资助机构 | Natural Science Foundation of Shaanxi Provincial Department of Education |
| 源URL | [http://119.78.100.186/handle/113462/45821]  |
| 专题 | 中国科学院近代物理研究所 |
| 通讯作者 | Song, Qi |
| 作者单位 | Northwest Univ, Inst Modern Phys, Xian 710069, Shaanxi, Peoples R China |
| 推荐引用方式 GB/T 7714 | Chen, Lei,Song, Qi,Zhou, Bo,et al. A theoretical explanation of RbBH4's fractionally occupied ground-state phase and the reorientational motion of the [BH4](-) group[J]. JOURNAL OF PHYSICS D-APPLIED PHYSICS,2017,50:12. |
| APA | Chen, Lei,Song, Qi,Zhou, Bo,Zhang, Xiaodong,&Jiang, Zhenyi.(2017).A theoretical explanation of RbBH4's fractionally occupied ground-state phase and the reorientational motion of the [BH4](-) group.JOURNAL OF PHYSICS D-APPLIED PHYSICS,50,12. |
| MLA | Chen, Lei,et al."A theoretical explanation of RbBH4's fractionally occupied ground-state phase and the reorientational motion of the [BH4](-) group".JOURNAL OF PHYSICS D-APPLIED PHYSICS 50(2017):12. |
入库方式： OAI收割
来源：近代物理研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。