[gmx-users] OPLS force field

Justin A. Lemkul jalemkul at vt.edu
Sat Jan 23 00:15:47 CET 2010

Yanmei Song wrote:
> Dear Users:
> I build up my polymer molecules in PRODRG and got the .gro and .itp 
> file. Then anyone knows how I can transfer or edit the itp file into 
> OPLS force field format?  Or anyone knows how can I get the OPLS force 
> field parameters if I have my molecule gro file.  Any suggestion will be 
> great thankful.

PRODRG is only suitable for use with Gromos96 force fields.  If you want to 
re-write it for OPLS, you're better off starting from scratch, since you'll have 
to change just about all of it, anyway.

There are several scripts in the User Contribution section of the Gromacs that 
can generate OPLS force fields.  You can also try x2top, but you will likely 
have to come up with .n2t entries to suit whatever your molecule is.


> -- 
> Yanmei Song
> Ph.D. Candidate
> Department of Chemical Engineering
> Arizona State University


Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080


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