C-GeM: Coarse-Grained Electron Model for Predicting the Electrostatic Potential in Molecules.

Area of Science:

• Computational chemistry
• Molecular modeling
• Physical chemistry

Background:

• Accurate prediction of molecular electrostatic properties is crucial for understanding chemical interactions.
• Existing methods like ab initio calculations are computationally expensive.
• Reactive force fields often struggle with accurate charge equilibration and describing dissociation.

Purpose of the Study:

• To develop a novel coarse-grained electron model, C-GeM, for efficient and accurate prediction of molecular electrostatic properties.
• To validate the C-GeM model's performance in describing molecular interactions and chemical processes.
• To highlight the advantages of C-GeM over traditional computational chemistry methods.

Main Methods:

• Developed C-GeM, representing atoms as a positive core and a Gaussian-distributed electron shell.
• Incorporated electronegativity into the core-shell interaction energy.
• Minimized electronic shell positions within the atomic core field to determine electrostatic properties.
• Tested C-GeM on molecules containing H, C, O, and Cl, including HCl dissociation.

Main Results:

• C-GeM accurately predicts electrostatic potentials for molecules containing H, C, O, and Cl.
• The model correctly describes the ionic dissociation of HCl in solution and neutral dissociation in the gas phase.
• Demonstrated rapid prediction of electrostatic potential surfaces.
• Showed accurate description of dissociation into integer charge fragments, facilitating redox reaction analysis.

Conclusions:

• C-GeM offers a computationally efficient alternative to expensive ab initio methods.
• The model accurately captures electrostatic properties and chemical processes like dissociation and polarization.
• C-GeM's unique features, such as non-atomic charge centers and no unphysical charge transfer, provide a more realistic representation of molecular electrostatics.