Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6.
Phys Chem Chem Phys. 2012 May 21;14(19):7005-11. doi: 10.1039/c2cp40160f. Epub 2012 Apr 10.
A combined experimental and theoretical study of hydrogen-rich ammonium borohydride (NH4BH4) subjected to pressures up to 10 GPa indicates two phase transitions, detected by synchrotron radiation powder X-ray diffraction, Raman spectroscopy and Car-Parrinello molecular dynamics calculations, at 1.5 and 3.4 GPa. The ambient pressure, face-centred cubic phase of NH4BH4 transforms into a highly disordered intermediate structure which then evolves upon increasing pressure into an orthorhombic, distorted CsCl structure. The structure of the latter phase was solved using ab initio computational techniques and from a Rietveld full pattern refinement of the powder X-ray diffraction data.
对高达 10 GPa 压力下的富氢氨基硼烷（NH4BH4）进行的综合实验和理论研究表明，通过同步辐射粉末 X 射线衍射、拉曼光谱和 Car-Parrinello 分子动力学计算，在 1.5 和 3.4 GPa 处检测到两个相变。在环境压力下，面心立方相的 NH4BH4 转变为高度无序的中间结构，然后随着压力的增加进一步演变为正交、扭曲的 CsCl 结构。后一相的结构使用从头算计算技术和粉末 X 射线衍射数据的 Rietveld 全谱精修来解决。
