Continuum treatment of electronic polarization effect

Area of Science:

• Computational chemistry
• Molecular modeling

Background:

• Accurate simulation of molecular interactions in different environments is crucial.
• Existing methods for electronic polarization in molecular mechanics (MM) can be computationally intensive or lack consistency across diverse dielectric media.

Purpose of the Study:

• To develop and validate a continuum treatment for electronic polarization within molecular mechanics simulations.
• To establish a consistent method for calculating atomic charges applicable across various dielectric environments.

Main Methods:

• Exploration of a continuum polarizable model for electronic polarization.
• Determination of an optimal interior dielectric constant (ε=4) through comparison with ab initio quantum mechanical calculations.
• Simultaneous fitting of atomic charges using quantum mechanical electrostatic fields from vacuum, low-dielectric organic solvents, and water.

Main Results:

• The continuum model with an interior dielectric constant of 4 demonstrates excellent agreement with high-level ab initio calculations.
• Model performance is robust and not significantly affected by the definition of molecular volume.
• A single set of atomic charges derived from this method is consistently applicable across different dielectric environments and molecular conformations.
• Atomic charges show good transferability from monomers to dimers.

Conclusions:

• The developed continuum polarizable model offers a consistent and efficient approach to electronic polarization in MM simulations.
• This method facilitates the use of consistent atomic charges across diverse environments, improving the reliability of simulations.
• The findings support the development of a continuum polarizable force field for enhanced simulations of biomolecules like proteins and nucleic acids in implicit solvents.