Bond-Dependent Thole Model for Polarizability and Spectroscopy.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Molecular Modeling

Background:

• Accurate calculation of molecular polarizabilities is crucial for understanding molecular properties and interactions.
• Existing models often struggle with accuracy for configurations far from the ground state.

Purpose of the Study:

• To develop a novel, accurate, and robust model for calculating molecular polarizabilities.
• To extend the Thole modified dipole interaction model by incorporating interatomic distance dependencies.
• To validate the model's performance across diverse molecular systems and configurations.

Main Methods:

• Development of the TholeL model, which treats atomic polarizabilities as explicit functions of interatomic distances.
• Utilizing the SCAN functional for electronic structure calculations.
• Application of the model to ab initio molecular dynamics simulations.

Main Results:

• The TholeL model demonstrates high accuracy in predicting molecular polarizabilities with minimal training set dependence.
• Accurate polarizabilities were obtained for configurations significantly deviating from ground state structures.
• The model successfully generated accurate Raman spectra for water and urea systems.

Conclusions:

• The TholeL model offers a significant improvement in calculating molecular polarizabilities.
• Its accuracy extends to non-equilibrium geometries, making it valuable for dynamic simulations.
• TholeL provides a reliable method for generating accurate Raman spectra from simulations.