[gmx-users] modify C6 directly in FF using sigma and epsilon
David van der Spoel
spoel at xray.bmc.uu.se
Thu Apr 5 21:36:25 CEST 2007
Ryogo Sugitani wrote:
> 2007/4/5, David van der Spoel <spoel at xray.bmc.uu.se>:
>> Ryogo Sugitani wrote:
>> > David,
>> > How about adding [ nonbond_params ] in your ff???nb.itp file
>> > as shown in p.88 of the user's manual?
>> > I believe it will override the default vdw interaction for that
>> > particular atom-type pair.
>> > (Assuming you want to use combination rule #1 just for that
>> atom-type pair)
>> > If I miss your point, please disregard this...
>> In gromacs 3.3 it will still use the same combination rule. However, in
>> older versions, possibly 3.2.1, this would work: use sig/eps for
>> generating a matrix and overriding it with C6/C12. We took that out
>> because it is hard to explain, and we thought it was unnecessary...
> Can we still override just parameters (not the combination rule) in ver
> I was going to use this feature for my calculation in near future, so
> I'm a little bit concerned.
yes but according to the same combination rule as specified on top.
David van der Spoel, PhD, Assoc. Prof., Molecular Biophysics group,
Dept. of Cell and Molecular Biology, Uppsala University.
Husargatan 3, Box 596, 75124 Uppsala, Sweden
phone: 46 18 471 4205 fax: 46 18 511 755
spoel at xray.bmc.uu.se spoel at gromacs.org http://folding.bmc.uu.se
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