[gmx-users] Question about creating new forcefield terms

Suchitra Konduri gtg072j at mail.gatech.edu
Mon Oct 24 23:19:05 CEST 2005

Hi all,
I need a clarification on my simulation method. I am new to Gromacs and I am
trying to do MD simulations on Gibbsite for which I want to use a modified
form of CFF91 forcefield that has cubic and quartic terms along with quadratic
terms. Since none of the forcefields in Gromacs i.e ffXXXXbon.itp have such as
definition for both bond-stretch and bond-angle terms  I assume  that I have
to create a new gibbsitebon.itp file and also create a new toplogy file to
include atom definitions. I have a pdb file for gibbsite from Material Studio
and I tried using PRODG to obtain a .itp file but the atom types of the
Gibbsite structure are not defined in the database.

Can someone please suggest me if there is a difefrent method of solving the

Thanks a lot for you help,

Suchitra Konduri
Graduate Student
Department of Chemical & Biomolecular Engineering
Georgia Institue of Technology
Tel: 404-894-8476.

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