论文标题
压力诱导的SNI4的非形态化机理：X射线衍射 - X射线吸收光谱研究
Mechanism of pressure induced amorphization of SnI4: a combined X-ray diffraction -- X-ray absorption spectroscopy study
论文作者
论文摘要
我们通过将SN和I K边缘X射线吸收光谱和粉末X射线衍射的实验细节研究了SNI4的非晶化过程，最高为26.8GPA。标准和反向蒙特卡洛延长X射线吸收良好结构（EXAFS）改进确认SNI4四面体是一个基本的结构单位，通过Crystalline I Phase-I Phase-IS-II期跃迁至3GPA，然后在20GPA以上的无晶相中保存。到目前为止，尚未开发的碘EXAF显示非常有用，并确认在26.8 GPA的无定形相中，碘碘短键的形成接近2.85Å。 Crystalline II期SN的协调数增加似乎被排除在外，而四面体单元的变形通过扁平化进行，从而使I-SN-I角平均角度保持接近109.5°。此外，我们在竞争的几何和电子效应下向SN近边缘结构的压力的影响提供了证据。
We have studied the amorphization process of SnI4 up to 26.8GPa with unprecedented experimental details by combining Sn and I K edge X-ray absorption spectroscopy and powder X-ray diffraction. Standards and reverse Monte Carlo extended X-ray absorption fine structure (EXAFS) refinements confirm that the SnI4 tetrahedron is a fundamental structural unit that is preserved through the crystalline phase-I to crystalline phase-II transition about 7 to 10GPa and then in the amorphous phase that appears above 20GPa. Up to now unexploited Iodine EXAFS reveals to be extremely informative and confirms the formation of iodine iodine short bonds close to 2.85Å in the amorphous phase at 26.8 GPa. A coordination number increase of Sn in the crystalline phase-II appears to be excluded, while the deformation of the tetrahedral units proceeds through a flattening that keeps the average I-Sn-I angle close to 109.5°. Moreover, we put in evidence the impact of pressure on the Sn near edge structure under competing geometrical and electronic effects.
