The geometric structure of silver-doped silicon clusters

Area of Science:

• Physical Chemistry
• Materials Science
• Computational Chemistry

Background:

• Understanding the structure of doped silicon clusters is crucial for developing new materials.
• Previous studies on transition-metal doped silicon clusters often show endohedral structures.
• The behavior of silver as a dopant in silicon clusters is not well-established.

Purpose of the Study:

• To investigate the structural properties of cationic silver-doped silicon clusters (Si(n)Ag+, n=6-15).
• To determine the location of the silver atom within the silicon cluster.
• To compare the binding behavior of silver with other transition metals like copper.

Main Methods:

• Infrared multiple photon dissociation (IRMPD) spectroscopy was used to probe cluster structures.
• Density functional theory (DFT) computations were employed for theoretical analysis.
• Basin-hopping global optimization was utilized to identify candidate structures.

Main Results:

• All studied Si(n)Ag+ clusters (n=6-15) exhibit exohedral structures with the silver atom on the surface.
• Silicon frameworks for n=7-9 feature a pentagonal bipyramidal building block.
• Larger clusters (n=10-12, 14, 15) adopt trigonal prism-based structures.
• Silver atoms bind to surface sites but are less coordinated and weakly bound compared to copper.

Conclusions:

• Silver doping in silicon clusters leads to unique exohedral structures, contrasting with endohedral structures observed for other dopants.
• The structural motifs of Si(n)Ag+ clusters are size-dependent.
• Silver exhibits weaker binding to the silicon framework than copper, suggesting differences in their chemical interactions.