2D-3D transition for cationic and anionic gold clusters: a kinetic energy density functional study

Area of Science:

• Computational chemistry
• Materials science
• Quantum mechanics

Background:

• Gold clusters exhibit unique electronic and structural properties.
• Accurate theoretical methods are needed to model gold cluster behavior.
• Previous studies show variability in theoretical predictions.

Purpose of the Study:

• To investigate the energetics and structures of cationic and anionic gold clusters.
• To evaluate the performance of meta-generalized gradient approximation (MGGA) functionals.
• To compare theoretical results with experimental data for validation.

Main Methods:

• Density functional theory (DFT) calculations.
• Employing M06-L and other MGGA functionals.
• Analyzing structural transitions (2D to 3D) for various cluster sizes.

Main Results:

• M06-L functional accurately reproduces experimental energetics for Au(n)+ (n=5-10) and Au(n)- (n=8-13).
• Predicted 2D-to-3D structural crossovers at n=8 for cationic and n=12 for anionic clusters.
• MGGA functionals show improved performance due to smaller gradient enhancement and combined kinetic energy information.

Conclusions:

• MGGA functionals, particularly M06-L, are essential for accurate modeling of gold cluster energetics and structures.
• The study provides insights into the factors governing 2D/3D transitions in gold clusters.
• This work validates the use of M06-L for predicting properties of small metal clusters.