FFParam

FFParam streamlines parametrization of CHARMM force fields by generating and optimizing parameters for additive CGenFF/CHARMM36 and Classical Drude polarizable force fields to support molecular modeling (MM) and molecular dynamics (MD) simulations.

Key Features:

• Supported force fields: Supports parametrization for additive CGenFF/CHARMM36 and Classical Drude polarizable force fields.
• Quantum mechanical calculations: Interfaces with Gaussian and Psi4 to derive initial parameters from electronic structure calculations.
• Molecular mechanics compatibility: Performs molecular mechanics calculations with CHARMM and OpenMM for evaluation and testing of parameters.
• Monte Carlo Simulated Annealing (MCSA): Implements Monte Carlo Simulated Annealing (MCSA) to fit partial atomic charges, atomic polarizabilities, and Thole scale parameters.
• LSFITPAR integration: Calls LSFITPAR for automated fitting of bonded parameters.

Scientific Applications:

• Force field development for CHARMM: Generate and optimize parameters for CHARMM-based force fields to improve accuracy of MM and MD simulations.
• Polarizable force field parametrization: Develop and refine Classical Drude polarizable parameters, including polarizabilities and Thole scaling, for polarizable MD studies.
• Parameter generation across chemical species: Produce parameters applicable to molecular simulations of various chemical species to support broader MD applications.
• Prediction of molecular properties: Provide optimized parameters aimed at improving predictions of molecular properties in simulations.

Methodology:

Derives initial parameters using quantum mechanical calculations with Gaussian and Psi4, evaluates parameters with CHARMM and OpenMM, applies Monte Carlo Simulated Annealing (MCSA) to fit partial atomic charges, atomic polarizabilities, and Thole scale parameters, and uses LSFITPAR for bonded parameter fitting.