Dear all,

what is the standard procedure to obtain GBSW parameters (radii) for new systems that have not been included in the regular parameters? I am aware you do it with FEP methods, but I was wondering is there any tutorial for it online?

If I understood correctly, I have four different systems, two with explicit and two with implicit solvents. I do short minimisation, equilibration and production of let say explicit solvent system. Then, I change charge of some of the atoms in the system for explicit and implicit solvent, but I start those with the last trajectory of dynamics. In the end I would have to extract free energy and from those data I get the unknown radius?

Can someone please explain me the standard procedure for it?

Thank you!