A Novel Classical Density Functional Theory Base on Multibody Potential and Its Application to the Formation of Metal Nanoclusters.

Metal nanoclusters are important materials in many fields due to their special sizes and properties. The key feature of metal nanoclusters lies in their multibody interactions, which differ significantly from conventional pairwise potentials. In this work, we propose a novel free-energy functional for multibody potential by introducing a weighted density approximation (WDA). Using the functional, we develop dynamic density functional theory (DDFT) for metal clusters. The theory nicely reproduces the melting temperature and internuclear distance of various metal clusters, and the corresponding atomistic structure is also consistent with the literature. In contrast, the pairwise potential model and MFA lead to incorrect results. We predict regular and irregular polyhedral clusters, depending on the attractive strength between metal atoms. The crystallization process exhibits nonlinearity and irreversibility, yet the clusters ultimately adopt spherical-like structures. These findings and the proposed model may provide valuable insights into future studies of metal nanoclusters.