Development and initial applications of an e-ReaxFF description of Ag nanoclusters

Area of Science:

• Computational materials science
• Nanotechnology
• Physical chemistry

Background:

• Metal nanocrystals are crucial for electronics, catalysis, and spectroscopy.
• Understanding nanocrystal nucleation and growth mechanisms, especially shape determination, remains a challenge.
• Existing models struggle to accurately capture the transition from 2D to 3D configurations in small metal clusters.

Purpose of the Study:

• To develop and validate a new e-ReaxFF potential for silver (Ag) nanoclusters.
• To accurately model the critical two-dimensional (2D) to three-dimensional (3D) structural transition in small Ag clusters.
• To demonstrate the potential of this new force field for simulating metal-related phenomena.

Main Methods:

• Parameterization of an e-ReaxFF potential for Ag nanoclusters (N ≤ 20 atoms).
• Inclusion of a novel four-body dihedral term to penalize 3D structures in small clusters.
• Validation against density-functional theory (DFT) and coupled-cluster calculations, compared with embedded atom method (EAM) potentials.

Main Results:

• The developed e-ReaxFF potential accurately reproduces the 2D-3D transition observed between Ag₅ and Ag₇ clusters.
• The four-body dihedral term effectively manages the energetic balance favoring 2D structures for small clusters.
• Demonstrated capability of e-ReaxFF for simulating redox reactions in silver halides and plasmon dynamics via molecular dynamics.

Conclusions:

• The parameterized e-ReaxFF potential provides a unique and effective solution for modeling the 2D-3D transition in small metal nanoclusters.
• This work represents the first application of e-ReaxFF to model metallic systems.
• The validated potential opens new avenues for simulating complex phenomena in metal nanochemistry and materials science.