A Polarizable Valence Electron Density Based Force Field for High-Energy Interactions between Atoms and Molecules

22 March 2024, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


High-accuracy molecular force field models suited for hot gases and plasmas are not as abundant as those geared towards ambient pressure and temperature conditions. Here we present an improved version of our previous electron- density based force field model that can account for polarization effects by adjusting the atomic valence electron contri- butions to match ab initio calculated Mulliken partial charges. Using a slightly modified version of the Hohenberg-Kohn theorem, we also present an improved theoretical formulation of our model when dealing with systems with degenerate ground states. Preliminary results obtained from this methodology for water dimer calculations using CCSD(T)/cc- pVTZ and CCSD(T)/CEP-31G level of theory are presented using an order ten approximation. Further improvements include the additional interaction components with fictitious non-spherically symmetric, yet atom-centered, electron densities and fitting the exchange and correlation coefficients against analytical expressions. The latter removes all unphysical oscillations that are observed in the previous non-polarizable variant of our force field.


Density Functional Theory
Molecular Force Field
Interaction Energies
Molecular Modeling

Supplementary materials

Supplementary Material: A Polarizable Valence Electron Density Based Force Field for High- Energy Interactions between Atoms and Molecules
Table with a new set of fitting parameters for the atomic electron densities for the full electron variant of our model, in which the last three Gaussian contributions correspond to the valence electron contributions. Exact mathematical expressions for the exchange and correlation functionals, and the fitted coefficients associated with them. Validation of our model against various small molecules.

Supplementary weblinks


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