Multiscale partial charge estimation on graphene for neutral, doped and charged flakes

Area of Science:

• Computational Chemistry
• Materials Science
• Condensed Matter Physics

Background:

• Graphene's unique electronic properties make it promising for catalysis.
• Accurate atomic partial charges are crucial for modeling graphene's behavior, especially under charged conditions.
• Existing methods for charge calculation can be computationally expensive for large systems.

Purpose of the Study:

• To investigate the impact of edges and nitrogen/boron doping on graphene flake atomic charges.
• To develop a computationally efficient model for accurate charge determination in graphene.
• To provide parameters for improving graphene force fields and guiding catalytic material design.

Main Methods:

• Applied minimal-basis iterative stockholder (MBIS) and restrained electrostatic potential (RESP) methods.
• Utilized results to fit a second-order atom-condensed Kohn-Sham DFT model (ACKS2).
• Calculated atomic partial charges, dipole, and local electric fields for graphene flakes.

Main Results:

• The ACKS2 model accurately determined partial charges in graphene flakes.
• The method achieved high accuracy with negligible computational cost for large flakes.
• Edge and dopant effects on charge distribution were quantified.

Conclusions:

• The developed ACKS2 model offers a significant improvement for simulating graphene.
• This approach enhances graphene force fields for charged states.
• The findings guide the design of graphene-based media for catalytic applications.