Metallic nanoparticles (NPs), owing to their unique physicochemical characteristics, have garnered significant attention across diverse scientific and technological domains. Their magnetic, electrical, optical, chemical, and catalytic properties can be finely controlled by tuning their size, shape, and composition, leading to their broad applicability in various fields. Specifically, gold (Au) NPs smaller than 3-5 nm exhibit elevated reactivity, making them suitable for use in a range of biomedical and catalytic applications. The high surface mobility of Au NPs is a characteristic feature that plays a critical role in determining their unique properties. This is particularly important in small NPs, where the high surface-to-volume ratio results in a significant proportion of atoms residing on the NP surface, displaying greater mobility compared to those in the bulk even at fairly low temperature The dynamic atomic rearrangements occurring on the NP surface significantly influence the optical, electronic, and catalytic properties. However, the high atomic mobility of NPs introduces substantial challenges for both experimental and theoretical investigations into NP structures. Given the highly dynamic nature of the atoms, capturing not just the static structure of NPs but also their real-time atomic dynamics is crucial. This understanding is key to fully grasp the behavior of Au NPs and effectively control their properties for different applications, thus the pressing demand for techniques capable of providing atom-level insights into the dynamic behavior of NPs.