Pressure-Driven Phase Transitions in NaBH4: Theory and Experiments
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- 作者：Eunja Kim ; Ravhi Kumar ; Philippe F. Weck ; Andrew L. Cornelius ; Malcolm Nicol ; Sven C. Vogel ; Jianzhong Zhang ; Monika Hartl ; Ashley C. Stowe ; Luke Daemen ; Yusheng Zhao
- 刊名：Journal of Physical Chemistry B
- 出版年：2007
- 出版时间：December 20, 2007
- 年：2007
- 卷：111
- 期：50
- 页码：13873 - 13876
- 全文大小：159K
- 年卷期：v.111,no.50(December 20, 2007)
- ISSN：1520-5207
文摘
We have investigated pressure-induced structural transitions in NaBH4 through density-functional theorycalculations combined with X-ray and neutron diffraction experiments. Our calculations confirm that thecubic phase is stable up to 5.4 GPa and an orthorhombic phase occurs above 8.9 GPa, as observed in X-raydiffraction experiments. Both the calculations and X-ray diffraction measurements identify an intermediatetetragonal phase that appears between 6 and 8 GPa; that is, between the cubic and orthorhombic phases. Thisresult is also confirmed by high-pressure neutron diffraction experiments performed on NaBD4. Our calculationsand X-ray diffraction measurements show that the space group of the orthorhombic phase above 8.9 GPa isPnma and the orthorhombic phase remains stable up to 30 GPa. The calculated equations of state are inexcellent agreement with experiments.