Polarizable charge equilibration model for predicting accurate electrostatic interactions in molecules and solids.

Area of Science:

• Computational Chemistry
• Materials Science
• Biochemistry

Background:

• Electrostatic interactions are crucial for chemical, biochemical, and material systems.
• Quantum mechanics (QM) accurately describes these interactions, but force field models have limitations.
• Existing charge models in force fields often lack accuracy in predicting electrostatic behavior.

Purpose of the Study:

• To introduce and validate a novel methodology, PQEq, for rapid and dynamic prediction of atomic charges and polarization.
• To improve the accuracy of electrostatic interactions in molecular simulations.
• To provide a versatile tool applicable to various chemical and material systems.

Main Methods:

• Developed the PQEq (Partial Equalization of Quasi-electronegativity) method.
• Described polarization using Gaussian-shaped electron density and constant chemical potential.
• Parameterized PQEq using experimental atomic properties for elements up to Nobelium (Z=102).
• Validated PQEq by comparing QM interaction energies with probe dipoles against PQEq predictions for ~30 molecules.

Main Results:

• PQEq accurately predicts atomic charges and polarization, crucial for electrostatic interactions.
• PQEq-based interaction energies show excellent agreement with QM calculations.
• PQEq outperforms common charge models like Mulliken, ESP, OPLS, and AMBER in accuracy.
• The method demonstrates accurate response to external electric fields.

Conclusions:

• PQEq offers a significant advancement in accurately modeling electrostatic interactions.
• The method's accuracy and dynamic nature make it suitable for diverse applications.
• PQEq can be integrated into existing force fields (e.g., OPLS, AMBER, CHARMM) to enhance simulations.