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Density-functional Calculation of Anisotropic Displacement Parameters and its Use for Improving Experimental X-ray and Neutron Diffraction

各向异性位移参数的密度泛函计算及其在改进 X 射线和中子衍射实验中的应用

基本信息

批准号：
348493721
负责人：
Professor Dr. Richard Dronskowski
金额：
--
依托单位：
Department of Chemistry
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/348493721?language=en
关键词：
Density functional Calculation Anisotropic Displacement

项目摘要

Because of new approaches covering dispersion interactions, DFT methods for modelling molecular crystals have significantly gained attraction. Our proposal goes beyond structural optimization of molecular solids, however: we intend to use DFT+D methods for phonon calculations on van-der-Waals dominated solids to arrive at first-principles displacement parameters. By doing so, we will evaluate which kind of dispersion correction is particularly suited for such question and which temperature range is appropriate for the (primarily) harmonic approximation. Likewise, potential restrictions as regards elemental composition, intermolecular interactions and cell size of the model systems will be investigated. Parallel to our theoretical studies, we will synthesize suitable molecular crystals and characterize them using diffraction in a large temperature range below room temperature but with the highest possible resolution. This very cooperation between theoretically and experimentally inclined structural chemists will guarantee, on the one hand, the reliable validation of even more advanced theoretical approaches in the making and, on the other hand, lead to an improved handling of experimental diffraction data. The first aspect will allow us to rudimentally include anharmonic motion based on experimentally derived expansion coefficients and, thus, to increase our method's scope. The second aspect alludes to unfolding the electron density and the thermal motion which is particularly helpful for crystal structures showing problems of contrast and correlation. We also expect certain advantages for the very ambitious question of experimental charge densities from highly resolved diffractional data: population parameters of atom-centered multipoles and displacement parameters are often strongly correlated; the use of calculated displacement parameters will allow for a more meaningful determination of these multipoles. Eventually, we would love to broadly establish our method such that it is perceived (and, hopefully, used) by other structural chemists. Hence, we plan to provide a self-explanatory web platform in addition to publications in peer-reviewed journals.

由于新的方法涵盖色散相互作用，DFT方法模拟分子晶体显着获得的吸引力。我们的建议超越了分子固体的结构优化，然而：我们打算使用DFT+D方法的声子计算范德华主导的固体，以达到第一原理位移参数。通过这样做，我们将评估哪种色散校正特别适合于这样的问题，以及哪个温度范围适合于（主要）谐波近似。同样，潜在的限制方面的元素组成，分子间的相互作用和细胞大小的模型系统将进行调查。与我们的理论研究平行，我们将合成合适的分子晶体，并在室温以下的大温度范围内使用衍射对其进行表征，但具有尽可能高的分辨率。理论和实验倾向的结构化学家之间的这种合作，一方面将保证更先进的理论方法的可靠验证，另一方面，导致实验衍射数据的处理得到改进。第一个方面将使我们能够基本上包括基于实验得出的膨胀系数的非谐运动，从而增加我们的方法的范围。第二个方面暗示展开电子密度和热运动，这对于显示对比度和相关性问题的晶体结构特别有帮助。我们还期望从高分辨衍射数据的实验电荷密度的非常雄心勃勃的问题的某些优势：人口参数的原子为中心的多极子和位移参数往往是强相关的，使用计算的位移参数将允许这些多极子的更有意义的确定。最终，我们希望广泛地建立我们的方法，以便被其他结构化学家感知（并希望使用）。因此，我们计划提供一个自我解释的网络平台，除了在同行评审的期刊上发表文章。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Neutron powder diffraction and theory-aided structure refinement of rubidium and cesium ureate

尿酸铷和铯的中子粉末衍射和理论辅助结构细化

DOI：
10.1515/znb-2015-0228
发表时间：
2016
期刊：
Zeitschrift für Naturforschung B
影响因子：
0
作者：
K. B. Sterri;V. L. Deringer;A. Houben;P. Jacobs;C. M. N. Kumar;R. Dronskowski
通讯作者：
R. Dronskowski

Displacement parameters from density-functional theory and their validation in the experimental charge density of tartaric acid

密度泛函理论的位移参数及其在酒石酸实验电荷密度中的验证