[gmx-users] Modify TIP4P to TIP4P-Ew

Justin Lemkul jalemkul at vt.edu
Fri Nov 21 22:48:27 CET 2014

On 11/21/14 4:41 PM, Cai wrote:
> Hi users,
> The re-parameterized TIP4P-Ew water model shows encouraging agreements with
> experimental results. Since it is now not available in GROMACS, I have to
> modify the TIP4P water model to TIP4P-Ew according to this paper.
> (Horn et. al. (2004). Development of an improved four-site water model for
> biomolecular simulations: TIP4P-Ew. *The Journal of Chemical Physics*,
> *120*(20),
> 9665–78).
> Q1:
> I know how to change the water parameters (angle, rOH, ...) in the topology
> file (***.top/itp) and implement the Ewald-summation (coulombtype = PME).
> Is that all? It seems the paper also include correction for LJ by
> multiplying switching function, adding LJ tail, and correction for
> pressure, which are not easy to do in GROMACS. Any suggestions for doing
> these?
> Q2:
> Is it possible to do that without touching the source code?

The TIP4P-Ew model is already available in all of the Amber force fields 
provided with Gromacs.



Justin A. Lemkul, Ph.D.
Ruth L. Kirschstein NRSA Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 629
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalemkul at outerbanks.umaryland.edu | (410) 706-7441


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