How to make oplsaa.ff .itp files for compounds with charge greater than 2

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Dear users,

I have tried to generate an OPLSAA.ff .itp file for a polymer with different charges. Using LIGPARGEN, it is possible to go up to a charge of ±2. Are there any alternatives to generate a topology file for compounds with charges greater than ±2?

Thank you!

2

Hi,
Could you please mention what molecule?
Basically, charges are dependent on a molecule you want to work on. Technically, you can modify charges if your project is in that direction.
And finally, I would recommend building your ff.itp from scratch rather than using LigPargen. This generator has already issues with rounding charges.

3

Thank you for your reply. I need to generate .itp file for polypyrrole contianing 4 repeating unit and charge +3. I am attaching the link of my pdb file

Thank you