An efficient, fragment-based electronic structure method for molecular systems: self-consistent polarization with...

Area of Science:

• Computational chemistry
• Theoretical chemistry
• Quantum chemistry

Background:

• Accurate simulation of molecular liquids is computationally demanding.
• Existing methods struggle to balance accuracy and efficiency for large systems.

Purpose of the Study:

• To develop a fragment-based electronic structure method for molecular liquids.
• To incorporate electronic polarization self-consistently while treating other interactions perturbatively.
• To achieve accurate and computationally efficient simulations.

Main Methods:

• Fragment-based electronic structure calculations.
• Self-consistent treatment of electronic polarization (induction).
• Pairwise symmetry-adapted perturbation theory for exchange and dispersion interactions.
• Exploitation of distance-dependent thresholds for linear scaling.

Main Results:

• Method achieves <1 kcal/mol average error on the S22 dimer database with appropriate basis sets.
• Recovers >90% of binding energy for water clusters up to (H2O)20.
• Demonstrates significant computational cost reduction compared to ab initio methods.

Conclusions:

• The developed method offers a promising route for accurate, systematically improvable, and parameter-free simulations of molecular liquids.
• The approach balances computational efficiency with high accuracy for condensed-phase systems.
• Enables large-scale electronic structure studies of complex molecular systems.