If the [ defaults ] sections are identical, you have just to add the items from [atoms], [bonds], etc sections of the new force field to the appropriate sections of the old force field.
The compatibility of these force fields is a sort of magic that is up to you. - Vitaly > I have a general question about mixing force fields. I want to try to > use CGenFF to model the drug and I wanted to use CHARMM for the > solvent. I see the general advice given online is to always use only > one forcefield but I know CGenFF was developed off CHARMM but > specifically for drugs. If anything, I would like to try it to see > how different results are from just using CGenFF. How would one go > about using two forcefields on your topology? For example below, would > one simply add the non-default FF to the default FF? > > ; File 'topol.top' was generated > ; By user: Administrator (500) > ; On host: fabian-3bef2d6a > ; At date: Fri April 1st 02:59 PM 2011 > ; > ; This is your topology file > ; DRUG SOLUTION w/ Ethanol > > ; Include forcefield parameters > #include "Charmm.ff" > #include "Cgenff.ff" > > > **Thanks for everyones help. > > -- > Best regards, > > Fabian F. Casteblanco > Rutgers University -- > Chemical Engineering PhD Student > C: +908 917 0723 > E: fabian.castebla...@gmail.com -- gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org. Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
