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

第一个资助期的主要成果是成功地进一步开发了无序分子体系的反蒙特卡罗模拟程序(RMC)，以及用于将X射线散射数据修正为绝对值的新的数据简化软件。结合随着这些发展而获得的高精度X射线散射数据，以及EXAFS数据，RMC为研究小组分别合成的一个非晶白光发生器(WLG)和一个宏观非晶二次谐波发生器(SHG)提供了第一批令人印象深刻的结构结果。到目前为止，仅限于两个系统的限制一方面是由于电晕大流行，另一方面也是因为我们在第一个资助期对研究工作所需人力的误判。在第二个资助期，现有的工具将应用于更多的有机和无机WLG，以确定结构-性质关系，可以解释这种影响仅限于非晶态材料的限制。在实验上，研究还将更多地扩展到中子散射实验，以了解有机配体之间的相互作用。最近的结果还表明，在{Sn4S6}-WLGS中存在硫网络，可以解释为振动网络。为了澄清这一点，将进行非弹性中子散射实验。然而，在非晶态系统中，所谓的超额振动密度是众所周知的长时间的(玻色峰)。这个问题也将在这里得到解决。

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.