标题： 结合X射线衍射和晶体结构预测识别α-SnWO4的高压相 显示英文标题

标题： Identification of the high-pressure phases of alpha-SnWO4 combining x-ray diffraction and crystal structure prediction

摘要： 我们已经表征了α-SnWO4在高压下的行为。使用金刚石压砧细胞和同步加速器粉末X射线衍射，该化合物已被研究到高达30 GPa的压力。我们报告了在我们的研究范围内压力范围内的两种结构相变的证据，并提出了两个高压相的晶体结构。第一个相变在大约12.9 GPa处被观察到，通过使用DICVOL指数和密度泛函理论计算结合得到了这一结果。第二个高压相在大约17.5 GPa处被观察到，通过使用CALYPSO代码确定，其预测得到了实验X射线衍射图的Le Bail拟合的支持。所提出的结构序列涉及单位晶胞体积的两次连续塌陷以及Sn和W原子配位数的增加。报告了{\alpha }-SnWO4和两个高压相的室温状态方程、压缩主轴及其可压缩性、弹性常数和弹性模量。 显示英文摘要

摘要： We have characterized the high-pressure behavior of alpha-SnWO4. The compound has been studied up to 30 GPa using a diamond-anvil cell and synchrotron powder X-ray diffraction. We report evidence of two structural phase transitions in the pressure range covered in our study, and we propose a crystal structure for the two high-pressure phases. The first one, observed around 12.9 GPa, has been obtained combining indexation using DICVOL and density-functional theory calculations. The second high-pressure phase, observed around 17.5 GPa, has been determined by using the CALYPSO code, the prediction of which was supported by a Le Bail fit to the experimental X-ray diffraction patterns. The proposed structural sequence involves two successive collapses of the unit-cell volume and an increase in the coordination number of Sn and W atoms. The room-temperature equations of state, the principal axes of compression and their compressibility, the elastic constants, and the elastic moduli are reported for {\alpha}-SnWO4 and for the two high-pressure phases.