手性影响的光诱导液态团簇成核、生长与性能关联规律的原位超快研究

原位高时空分辨下观测团簇成核与生长的动力学过程具有挑战性，但这对理解自然界物质转化规律具有重要意义。过去由于受表征手段的限制，在超高时空尺度下研究团簇成核机制和生长演化规律的报道很少。利用近些年出现的四维超快电镜技术，本项目拟采用超快电子成像-衍射-能谱“复合”模式，进行“拍电影”式原位可视化研究手性影响的液态团簇成核与生长动力学过程，以尽可能获得互补而全面的动态演变信息。同时，利用超快扫描电镜的二次电子和光学探测系统研究不同时刻下的团簇结构与其载流子过程、光学性能的关联规律。本项目将推动超快可视化“复合”模式的实验观测在团簇方面的新发现，从而从本质上清晰的揭示手性影响的液态团簇成核与生长机制，以及构筑团簇结构-性能一一对应的关联规律，并最终为手性合成、催化及制药领域提供科学技术指导。

In situ observation of nucleation and growth processes of clusters with high spatiotemporal resolution remains a challenge. However, this is important for exploring and understanding fundamental phenomena occurred in nature. Owing to the technical limitations in the past years, there were few reports on direct visualization of light-induced dynamics of cluster nucleation and growth with high spatiotemporal resolution. Using ultrafast imaging, diffraction and spectroscopy modes in 4D electron microscopy, this proposal aims to study the chirality-related ultrafast dynamics of the nucleation and growth of liquid clusters under femtosecond laser pulse excitation. The captured comprehensive information will be constructed into “movie-like” features showing transient states in the undergoing process. Meanwhile, the real-time structure-property relationship in the clusters will be investigated by ultrafast optical characterization integrated in scanning ultrafast electron microscopy. In this regard, the mechanisms underlying the observed dynamics will be revealed. The outcome of this proposal is expected to provide new understanding of the nucleation and growth in clusters and new insights for chirality-related synthesis, catalysis and drug production.