Robust molecular representations for modelling and design derived from atomic partial charges

Area of Science:

• Computational chemistry
• Quantum chemistry
• Molecular modeling

Background:

• Atomic partial charges represent molecular electron density.
• Ab initio methods derive these charges from fundamental quantum mechanical principles.
• The choice of partial charge scheme can impact molecular descriptor quality.

Purpose of the Study:

• To evaluate different ab initio derived atomic partial charge schemes.
• To assess their suitability for constructing molecular descriptors.
• To identify conformation-independent charge schemes for molecular modeling.

Main Methods:

• Derivation of atomic partial charges using ab initio quantum chemistry methods.
• Evaluation of various partial charge schemes (e.g., NPA, CM5).
• Assessment of charge scheme conformation-dependence.

Main Results:

• Ab initio derived atomic partial charges offer a simple yet informative representation of molecular electron density.
• Natural Population Analysis (NPA) and Charge Model 5 (CM5) charges were found to be largely conformation-independent.
• These conformation-independent charges are suitable for molecular descriptor construction.

Conclusions:

• Atomic partial charges derived from ab initio calculations are valuable for understanding electron density.
• NPA and CM5 charge schemes are recommended for molecular modeling and design due to their conformation independence.
• These findings facilitate the development of more robust molecular models.