Core-shell potential-derived point charges.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Molecular Modeling

Background:

• Accurate representation of molecular electrostatic potential is crucial for understanding chemical interactions.
• Existing atomic point charge models have limitations in describing charge distribution.
• Distributed multipole models offer improvements but can be computationally intensive.

Purpose of the Study:

• To develop and validate a novel core-shell model for calculating potential-derived point charges.
• To assess the performance of the core-shell model against established methods.
• To investigate the optimization of shell charges and positions within the model.

Main Methods:

• Development of a core-shell atomic model where each atom is divided into a static core and a variable-charge, variable-position shell.
• Optimization of shell charges and positions to best reproduce ab initio molecular electrostatic potential.
• Comparison of the core-shell model's electrostatic potential description with potential-derived net atomic point charges and distributed multipoles.

Main Results:

• The core-shell model significantly improves the description of ab initio electrostatic potential compared to net atomic point charge models.
• The model's accuracy is also superior to distributed multipoles up to atomic quadrupole moments.
• Results obtained from the core-shell model are comparable to those from the Weller-Williams lone-pair model.

Conclusions:

• The core-shell model provides a more accurate and robust method for deriving point charges from ab initio molecular electrostatic potential.
• This model offers a valuable alternative to existing methods, particularly for systems requiring precise electrostatic descriptions.
• Further investigation into implementation differences with other advanced models is warranted.