Structures of gas-phase Ag-Pd nanoclusters: a computational study.

Area of Science:

• Computational chemistry
• Materials science
• Nanotechnology

Background:

• Silver-palladium (Ag-Pd) clusters are important in catalysis and materials science.
• Accurate modeling of their structure is crucial for understanding their properties.
• Previous empirical potentials had limitations in reproducing density-functional theory (DFT) results.

Purpose of the Study:

• To develop and validate improved empirical potentials (EPs) for Ag-Pd clusters.
• To investigate the structural properties of gas-phase Ag-Pd clusters using a combined DFT/EP approach.
• To assess the accuracy of reparametrized EPs against DFT calculations.

Main Methods:

• Combined density-functional theory (DFT) and empirical potential (EP) methods.
• Reparametrization of many-body EPs for Ag-Ag, Pd-Pd, and Ag-Pd interactions.
• Global optimization searches for cluster structures at various sizes (38-100 atoms) and compositions (25%, 50%, 75%).
• Reoptimization of low-energy isomers at the DFT level.

Main Results:

• Reparameterized EPs demonstrate significantly improved agreement with DFT results compared to original potentials.
• Both methods consistently identify the lowest-energy isomers across different sizes and compositions.
• Energy differences between isomers show good qualitative agreement, particularly for larger clusters (60 and 100 atoms).

Conclusions:

• The reparametrized EPs provide a reliable and computationally efficient method for studying Ag-Pd clusters.
• This approach extends the feasibility of structural investigations to larger cluster sizes.
• The validated EPs are suitable for large-scale simulations where DFT is prohibitive.