Charge equilibration model with shielded long-range Coulomb for reactive molecular dynamics simulations.

Area of Science:

• Computational Chemistry
• Electrochemistry
• Materials Science

Background:

• Accurate atomic descriptions of electrochemical systems necessitate reactive potentials accounting for charge distribution and polarization.
• Existing models like charge equilibration (QEq) often truncate Coulomb interactions at short distances for computational efficiency, limiting their applicability to large systems.

Purpose of the Study:

• To extend the charge equilibration (QEq) method to incorporate long-range Coulomb interactions.
• To improve the atomic-level simulation of electrochemical systems, particularly those with significant electrostatic effects over extended distances.

Main Methods:

• Development and application of an extended QEq method incorporating long-range Coulomb effects.
• Validation through charge calculations on metal-organic frameworks and simple molecular systems.
• Integration with Ewald summation for force calculations in capacitor configurations.

Main Results:

• The extended QEq method provides a more accurate representation of partial charge distribution compared to the standard QEq approach.
• Calculations incorporating long-range Coulomb interactions showed noticeable differences, particularly in capacitor models.
• The Ewald summation method, when combined with the extended QEq, proved superior for describing electrostatics in charged electrodes.

Conclusions:

• The extended QEq method accurately accounts for long-range electrostatic interactions in molecular systems.
• This approach enables more realistic atomic simulations of electrochemical devices, including batteries and solid-state memory, by considering electrode effects across the dielectric layer.