[gmx-users] Mixing Force Fields
Mark.Abraham at anu.edu.au
Fri Oct 14 17:38:53 CEST 2011
On 15/10/2011 2:23 AM, Fabian Casteblanco wrote:
> Hello community,
> 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.
It won't Just Work because you cannot have two [defaults] sections.
There may be other such issues. Reading chapter 5 of the manual will be
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