Carbon Doping in Small Lithium Clusters: Structural, Energetic, and Electronic Properties from Quantum Monte Carlo...

Area of Science:

• Materials Science
• Computational Chemistry
• Quantum Mechanics

Background:

• Lithium clusters are fundamental units in materials science.
• Understanding dopant effects is crucial for tuning material properties.
• Carbon's unique electronic structure makes it an interesting dopant.

Purpose of the Study:

• To investigate the impact of carbon atom doping on the energetic and structural properties of small lithium clusters.
• To quantify changes in binding energy, dissociation energy, bond length, and coordination number.
• To provide insights into the enhanced stability of carbon-doped lithium clusters.

Main Methods:

• Density Functional Theory (DFT) for electronic structure calculations.
• Diffusion Quantum Monte Carlo (DMC) for highly accurate energy calculations.
• Hartree-Fock (HF) approximation for comparative analysis.
• Systematic variation of cluster size and composition.

Main Results:

• Carbon doping substantially increases the binding energy of lithium clusters (0.261 ± 0.008 to 1.048 ± 0.003 eV).
• Dissociation energy for carbon removal is significantly higher (-7.65 ± 0.02 to -3.33 ± 0.01 eV) than for lithium removal (-2.81 ± 0.02 to -0.78 ± 0.02 eV).
• Carbon substitution leads to reduced bond lengths (approx. 1.00 Å) and coordination numbers (up to 2.78).

Conclusions:

• Carbon doping demonstrably enhances the overall stability of lithium clusters.
• The observed changes in energetic and structural properties confirm carbon's role in strengthening cluster bonds.
• Findings align with existing theoretical and experimental data, validating the computational approach.