[gmx-users] using different force fields

[Erik Lindahl]

Hi Michael,

> 
> I am fairly new to GROMACS and would like to use the ffgmx2 force field 
> for the system I am working with as to maintain the hydrogens in my 
> system as separate atoms and not part of a composite atom as in the 
> ffgmx force field. However I am having a hard time getting GROMACS to 
> read from the ffgmx2 files. I haven't found any reference to this 
> problem in the documentation and would appreciate any help those of you 
> who are more experienced than myself can provide. Thank you in advance 
> for any information you can offer.
> 

First, if you want all-atom, I'd recommend opls instead of ffgmx2. It's 
present in gromacs 3.1.4 and later.

Second, your problem description is rather vague, so we won't be able to 
help you unless you provide us with some examples of output or errors!

Cheers,

Erik