A Universal and Straightforward Approach to Include Penetration Effects in Electrostatic Interaction Energy...

Area of Science:

• Computational Chemistry
• Molecular Modeling
• Quantum Chemistry

Background:

• Classical force fields often lack explicit treatment of charge penetration, limiting accuracy in electrostatic interactions.
• Accurate modeling of electrostatic interactions is crucial for understanding molecular behavior and chemical processes.

Purpose of the Study:

• To develop a novel charge-distribution model, augmented promolecule (aug-PROmol), to address the limitations of classical force fields regarding charge penetration.
• To evaluate the performance of the aug-PROmol model in approximating electrostatic energy.

Main Methods:

• The aug-PROmol model is based on the superposition of spherical atomic electron densities derived from SCF energy-optimized atomic orbitals.
• Atomic densities are rescaled using partial point charges obtained from molecular electrostatic potential fits.
• The model was validated using the S66 benchmark dataset, including nonequilibrium geometries.

Main Results:

• The aug-PROmol model requires no additional parametrization beyond point charges.
• It demonstrates good agreement in approximating electrostatic energy, with a Root Mean Square Error (RMSE) of 0.76 kcal/mol when compared to DFT-SAPT (B3LYP/aug-cc-pVTZ).

Conclusions:

• The aug-PROmol model offers a computationally efficient and accurate approach to incorporating charge penetration effects in molecular simulations.
• This method provides a valuable tool for enhancing the predictive power of classical force fields in computational chemistry.