Gajda Roman, Stachowicz Marcin, Makal Anna, Sutuła Szymon, Parafiniuk Jan, Fertey Pierre, Woźniak Krzysztof
Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Żwirki i Wigury 101, Warszawa 02-093, Poland.
Institute of Geochemistry, Mineralogy and Petrology, Department of Geology, University of Warsaw, Żwirki i Wigury 93, Warszawa 02-089, Poland.
IUCrJ. 2020 Mar 7;7(Pt 3):383-392. doi: 10.1107/S2052252520001955. eCollection 2020 May 1.
X-ray diffraction studies of crystals under pressure and quantitative experimental charge density analysis are among the most demanding types of crystallographic research. A successful feasibility study of the electron density in the mineral grossular under 1 GPa pressure conducted at the CRISTAL beamline at the SOLEIL synchrotron is presented in this work. A single crystal was placed in a diamond anvil cell, but owing to its special design (wide opening angle), short synchrotron wavelength and the high symmetry of the crystal, data with high completeness and high resolution were collected. This allowed refinement of a full multipole model of experimental electron distribution. Results are consistent with the benchmark measurement conducted without a diamond-anvil cell and also with the literature describing investigations of similar structures. Results of theoretical calculations of electron density distribution on the basis of dynamic structure factors mimic experimental findings very well. Such studies allow for laboratory simulations of processes which take place in the Earth's mantle.
对处于压力下晶体的X射线衍射研究以及定量实验电荷密度分析，属于最具挑战性的晶体学研究类型。本文介绍了在SOLEIL同步加速器的CRISTAL光束线进行的一项关于1吉帕压力下钙铝榴石矿物电子密度的成功可行性研究。将单晶置于金刚石对顶砧中，由于其特殊设计（宽开口角）、同步加速器波长较短以及晶体的高对称性，收集到了具有高完整性和高分辨率的数据。这使得能够对实验电子分布的完整多极模型进行精修。结果与在无金刚石对顶砧情况下进行的基准测量一致，也与描述类似结构研究的文献一致。基于动态结构因子的电子密度分布理论计算结果与实验结果非常吻合。此类研究能够对发生在地幔中的过程进行实验室模拟。
