simtk.org

Hi,

I would like to simulate a small molecule with explicit solvent in OpenMM. I have created CHARMM force field files using CGenFF:https://cgenff.paramchem.org/. My question is whether it is possible to straightforwardly solvate this molecule and simulate it using an arbitrary explicit water model (e.g. qTIP4P/f). One route that I think might work is: (1) serialize the force field using the xmlserializer in OpenMM, (2) create a force field object by loading a list of xml files, e.g.


Do you think this is feasible? If not with CHARMM, would it be with Amber?

Thank you!
Joe

If you're already starting from CHARMM files, what about just loading them directly with CharmmPsfFile?

Peter

Hi Peter,

I am able to do that currently to run a gas phase simulation or a simulation in implicit solvent, but would I be able to load the charmm files directly, solvate the molecule, and run the simulation in explicit water (using e.g. TIP4P)?

Thank you!
Joe

No, you would have to solvate the molecule with CHARMM or something equivalent. You could solvate in VMD and use autopsf to create the PSF file, or you could use CHARMM-GUI if you don't have access to CHARMM directly.

We're currently working on a CHARMM FF conversion, but it's not quite ready yet.