Simultaneous parametrization of torsional and third-neighbor interaction terms in force-field development: The LLS-SC...

Area of Science:

• Computational Chemistry
• Molecular Modeling
• Force Field Development

Background:

• Force field development commonly calibrates torsional terms using conformational energies.
• Optimization of third-neighbor nonbonded interactions, crucial for torsions, receives less attention.
• Accurate force fields are essential for reliable molecular simulations.

Purpose of the Study:

• To introduce and validate the LLS-SC algorithm for simultaneous parametrization of torsional and third-neighbor terms.
• To enhance the accuracy of molecular force fields by addressing coupled interactions.
• To provide a computational tool for improved force field development.

Main Methods:

• Developed the LLS-SC algorithm, employing a self-consistent procedure.
• Each iteration combines linear least-squares (LLS) regression with geometry optimization.
• Applied the method to aliphatic chains within the GROMOS 53A6 united-atom force field.

Main Results:

• Successfully parametrized torsional and third-neighbor interaction terms simultaneously.
• Demonstrated proof-of-principle for the LLS-SC method on aliphatic chains.
• The optimized parameters were compared against a manually fitted set.

Conclusions:

• The LLS-SC algorithm offers a robust approach for simultaneous force field parameter optimization.
• This method addresses the strong coupling between torsional and third-neighbor interactions.
• The LLS-SC implementation is publicly available for broader use in force field development.