Determination of Structural Correlations in Amorphous Materials by Means of Synchrotron- and Neutron Scattering and Reverse Monte-Carlo-Simulations

在第一个资助期间的主要成果是成功地进一步开发了用于无序分子系统的反向蒙特卡罗模拟程序（RMC）和用于将x射线散射数据校正为绝对值的新数据简化软件。与这些发展提供的高精度x射线散射数据以及EXAFS数据相关，RMC为研究组合成的一个非晶白光发生器（WLG）和一个宏观非晶次谐波发生器（SHG）提供了第一个令人印象深刻的结构结果。到目前为止，只有两个系统的限制一方面是冠状病毒大流行的结果，另一方面也是我们在第一个资助期对研究工作所需人力的错误判断的结果。在第二个资助期，现在可用的工具将应用于其他有机和无机wlg，以确定结构-性质关系，可以解释这种效应仅限于非晶材料的局限性。实验方面，研究还将进一步扩展到中子散射实验，以了解有机配体之间的相关性。最近的研究结果还表明，{Sn4S6}-WLGs中存在一个硫网络，可以解释为一个振动网络。将进行非弹性中子散射实验来澄清这一点。然而，所谓的非晶态的超振动密度长期以来是众所周知的（玻色峰）。这个问题也将在这里讨论。

Main results during the first funding period were the successful further development of a Reverse Monte Carlo simulation program (RMC) for disordered molecular systems and new data reduction software for the correction of X-ray scattering data to absolute values. In connection with high-precision X-ray scattering data made accessible with these developments, but also with EXAFS data, the RMC provided first impressive structural results for one amorphous White Light Generator (WLG) and one macroscopic amorphous Second-Harmonics Generator (SHG) each synthesized in the research group. The limitation to only two systems so far is a consequence of the Corona pandemic on the one hand, but also of the misjudgment of the manpower needed for our research work in the first funding period.In the second funding period, the tools now available will be applied to additional organic and inorganic WLGs to identify structure-property relationships that can explain the limitation of this effect to just amorphous materials. Experimentally, the studies will also be more extended more to neutron scattering experiments to understand the correlations between the organic ligands.Recent results also suggest the existence of a sulfur network in the {Sn4S6}-WLGs, which could be interpreted as a vibrational network. Inelastic neutron scattering experiments will be performed to clarify this. So-called excess vibrational densities of states in amorphous systems are however well known for long (Bose peak). This question will be addressed here as well.