Force Field Parameter Generation

The atomic charge definition is important in generating the force field parameters for MD simulations. Here, we provide the tool set for fitting three types of atomic charges for a given small molecule. You can upload the small molecule file in pdb/xyz format, draw the molecule, or paste the SMILES in the text box below. Note that deriving the ESP and RESP charges can take 2-10 hours depending on the size of your molecule and the functional and basis sets you selected. Further support for a protein in complex with a covalent ligand will be implemented with the support for automatically fitting the force field parameters for covalent MD.

Upload a Ligand file or a protein/covalent-ligand complex PDB file

Please upload the file in one of the following formats: .smi, .pdb, .xyz, .sdf, and .mol2

Choose file

Paste the SMILES

Charge

Multiplicity

Charge type

BCC

Advanced Options

Functional

Hartree-Fock is used by default, you can also specify your preferred functional

Basis

The default basis set is aug-cc-pvtz, you can also specify your favorite basis set here

Cores

By default you can only use 8 CPU cores and 16GB memory for a job. Upgrade to subscribed user for using more CPU cores and memory

Mem

By default you can only use 8 CPU cores and 16GB memory for a job. Upgrade to subscribed user for using more CPU cores and memory

Also calculate EI (ev)

If checked, the EI values will also be calculated at the level of B3LYP/6-31G

Perform optimization before calculation?

If checked, the geometry optimization at B3LYP/6-31G level will be performed first before the property calculations

Submit

Load Example