Aspherical atom-model developing novel methods for crystal structure determination of partially disordered materials

该项目旨在将非球面原子模型应用到总散射数据的解释中。我们期望对有机物质紊乱背后的驱动力的理解有显著的提高。正如最近所显示的，非球面原子模型显然可以更好地分析结构参数，特别是对于像氢这样的轻原子。由于这些光原子在分子的局部排列中起着至关重要的作用，而分子的局部排列反过来又对无序负责，我们将能够更好地理解局部秩序变化的原因。为了实现这一目标，我们将在DISCaMB库中编码的AAM模型实现到DISCUS程序套件中，该程序套件旨在模拟无序结构和纳米颗粒。这不仅可以模拟单晶衍射数据（如几个可用的软件所做的那样），而且还可以扩展当前AAM在无序材料上的适用性。这是因为DISCUS软件已经可以用于粉末衍射的建模，对分布函数（PDF）， 3D-PDF和3D-delta-PDF， DISCUS中的DISCaMB的实现将立即允许在单晶布拉格衍射类型以外的数据集的情况下使用AAM。该项目的主要思想是将AAM模型应用于新型衍射数据集：粉末衍射、对分布函数（PDF）、3D-PDF和3D-delta-PDF。这是一项全新的、具有挑战性的任务，以前从未进行过调查。AAM在散射建模中的应用，如果成功的话，肯定会使人们更好地理解以前不能很好地理解的一类新材料。据我们所知，以前没有使用AAM进行粉末衍射的例子（除了一个例外），对分布函数（PDF）， 3D-PDF和3D-delta-PDF。这意味着我们的项目是该领域的先驱。在DISCUS中实施AAM将需要在已知和已发布的结构数据上对新软件进行测试，并在模型样品上测量单晶和粉末衍射数据。最后，我们将把新建立的方法应用于新的、有趣的主要有机材料的类别，这些材料已经显示出显著的漫射散射水平。新创建的计算机软件（包含DISCaMB库的DISCUS）将免费提供，项目的发现将与社区共享。

The project aims to implement aspherical atom models into the interpretation of total scattering data. We expect a significant improvement for the understanding of the driving forces behind disorder in organic matter. As recently shown, aspherical atom models allow a clearly better analysis of structural parameters, especially those for light atoms such as Hydrogen. As these light atoms play a crucial role in the local arrangement of the molecules, which are in turn responsible for the disorder, we will be able to understand the reasons for varying local order at a much better level. To achieve this goal we will implement the AAM modeles encoded in the DISCaMB library into our DISCUS program suite, which is designed to simulate disordered structures and nanoparticles. This will not only allow to model single crystal diffraction data (as several available pieces of software do) but also to extend frontiers of current applicability of AAM onto disordered materials. This is because DISCUS software can already by used for modeling of powder diffraction, Pair Distribution Function (PDF), 3D-PDF and 3D-delta-PDF and the implementation of DISCaMB in DISCUS will immediately allow the use of AAM in the case of datasets other than single crystal Bragg diffraction type. The main idea behind the project is to apply AAM models to new kinds of diffraction datasets: powder diffraction, Pair Distribution Function (PDF), 3D-PDF and 3D-delta-PDF. This is a completely new, challenging task where no previous investigations have been performed. The application of AAM to modeling of diffuse scattering, if successful, will surely allow much better understating of a new classes of materials which could not be well understood before. To our best knowledge there is no previous examples of using of AAM to powder diffraction (with one exception), Pair Distribution Function (PDF), 3D-PDF and 3D-delta-PDF. This means our project is a pioneer in that field. The implementation of AAM into DISCUS will require both tests of the new software on already known and published structural data, and measurements of single crystal and powder diffraction data on model samples. Finally, we will apply newly established methods to new, interesting classes of mainly organic materials already showing significant level of diffuse scattering. The newly created computer software (DISCUS with DISCaMB library incorporated) will be freely available and the finding of the project will be shared with the community.