hessff

hessff is a Windows desktop application for deriving bonded force-field parameters from external quantum-chemistry Hessians.

It currently supports:

• Gaussian .fch / .fchk
• ORCA .hess
• CP2K vibrational output plus bonded geometry
• Geometry + external Cartesian Hessian
• DRIH, IHF, FHF, and PHF
• GROMACS .itp
• LAMMPS data + parameter files

What It Does

The app reads a structure and a Cartesian Hessian, derives harmonic bond, angle, and rigid-dihedral parameters, and writes:

• parameters.json
• GROMACS topology fragments
• LAMMPS data and parameter files

Supported Geometry Files

• .xyz
• .mol2
• .pdb
• .cif

Notes

• .mol2 is the best choice when you already have bonded connectivity.
• .pdb and .cif can carry periodic cell information.
• For CP2K, use the dedicated CP2K Output mode with a geometry file.
• The app includes in-app help for accepted formats and method descriptions.

Included Binary

• hessff-gui.exe

License

This release is intended to be distributed under the MIT License.

• See LICENSE for the full license text.
• The MIT License allows binary-only distribution.
• Keep the copyright and license notice with the release.