[gmx-users] New LJ parameters for CH2/3-OW

David van der Spoel spoel at xray.bmc.uu.se
Mon Apr 8 22:33:30 CEST 2002

On Mon, 8 Apr 2002, Pedro Alexandre de Araujo Gomes Lapido Loureiro wrote:

>I want to use the LJ parameters for CH2/3-OW interaction of van Buuren et al (J.
>Phys. Chem. 97, 9206 - 1993).
>I have created a new ff*.* forcefield to edit the values.
>My questions are: in the ff*nb.itp file ...
>1) ... do I have to edit the [atomtypes] field ?
>2) ... do I have to edit the [nonbond_params] field ?
>3) ... does it suffice to edit the [ pairtypes ] field ?

Actually, very similar parameters are already in the ffgmx force field, it
is basically gromos87 + this correction + hydrogens on aromatic groups.

Otherwise the gromos96 forcefield contains a similar patch.

Otherwise for lipid like molecules check out Peter Tielemans parameters
(see link on www.gromacs.org)

Otherwise you can edit either the atomtypes (and make sure the CH2/3-OW
interaction is not in the nonbondtypes), or edit the nonbonded types.
Not that for alkane chains you want the ryckaert bellemans dihedrals.

Groeten, David.
Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
Husargatan 3, Box 576,  	75123 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://zorn.bmc.uu.se/~spoel

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