Modelling Cluster Structures and Properties at Different Length Scales

发现了一种新的基于类金刚烷团簇材料的光谱宽带白光发射器。这种材料与廉价、低功率的连续波红外激光二极管相结合，有可能用于高亮度应用。第一个研究的簇状材料[(StySn)4S6]由一个饱和有机苯乙烯配体的硫化锡基类金刚烷核组成。对金刚烷核组成修饰团簇和不同有机配体的研究表明，产生白光需要宏观结构的紊乱。此外，对于不产生白光的星系团，还发现了另一种非线性光学效应，即基波激光的二次谐波产生。最近的研究表明，需要了解团簇材料的结构和电子特征以及潜在的非线性光学效应，以便设计和微调团簇材料以达到所需的性能。这个理论研究项目将集中于计算和模拟单团簇的几何结构直至固态材料以及相关的电子和振动特性。因此，将考虑簇核和有机配体的许多变化。该项目将与C2 （Sanna）的理论项目密切合作，该项目以非线性光学效应的建模为重点，并与课题组的所有实验组合作。对单团簇和小团簇的系统研究将有助于确定白光或二次谐波产生团簇的结构和性质的趋势。基于对团簇相互作用的基本结构特征的理解，非晶状固态团簇结构的建模将有助于理解团簇材料的短期和长期顺序及其操作。该研究将回答集群相互作用如何受到集群组成的影响的问题。在不同长度尺度上相互连接的团簇材料的计算将允许结构和属性相关的见解，有利于优化所需的非线性光学效果。

A new spectrally broad band white light emitter based on adamantane-like cluster material has been discovered. This material in combination with cheap, low-power continuous-wave infrared laser diodes has the potential to be used in high-brilliance applications. The first investigated cluster material [(StySn)4S6] consists of a tin-sulfide-based adamantane-like core saturated with organic styrene ligands. Investigations of clusters with modified adamantane core composition and different organic ligands suggest that a disorder in the macroscopic structure is required to generate white light. Furthermore, another nonlinear optical effect, namely the second harmonic generation of the fundamental laser light, was found for clusters that show no white light generation. The recent studies demonstrate the need to understand the structural and electronic features of the cluster material as well as the underlying nonlinear optical effects in order to design and fine-tuning cluster materials to the desired properties. This theoretical research project will focus on the calculation and modelling of the geometric structures of single clusters up to solid state material and related electronic and vibrational properties. Therefore, numerous variations of the cluster core and the organic ligands will be considered. The project will closely collaborate with the theoretical project of C2 (Sanna) which focuses on the modelling of the nonlinear optical effects and all experimental groups of the research group. The systematic study of single clusters and small cluster agglomerates will allow to identify trends in structure and properties of white light or second harmonic generating clusters. Based on the understanding of the fundamental structural features of the cluster interaction, modeling of amorphous-like solid state cluster structures will contribute to the understanding of short- and long-range order in the cluster material as well as its manipulation. The study will answer the question how the cluster interaction can be influenced by cluster composition. The calculation of the cluster material at different length scales connected to each other will allow structural and property-related insights beneficial to an optimization for desired nonlinear optical effects.