[gmx-users] OPLS/AA + TIP5P, anybody?

Christopher Neale chris.neale at mail.utoronto.ca
Fri Sep 27 04:58:00 CEST 2013

Dear Gigo:

I've never used tip5p, but perhaps you could add some LJ terms to the opls_120 definition,
do your minimization, then remove the fake LJ term on opls_120 and run your MD?

If that doesn't work, then you might be able to minimize your system using FLEXIBLE tip3p
water and then use a script to convert the tip3p into tip5p. I expect that you can set 0,0,0
coordinates for each of the tip5p dummy atoms and that they will get correctly positioned 
in your first mdrun step with tip5p.


-- original message --

Dear Mark,
Thank you for your reply. Unfortunately, TIP5P is completely rigid and 
the FLEXIBLE define will not change it. Any other ideas?

On 2013-09-24 23:51, Mark Abraham wrote:
> You should be able to minimize with CG and TIP5P by eliminating
> constraints, by making the water use a flexible molecule, e.g. define
> = -DFLEXIBLE (or something). Check your water .itp file for how to do
> it.
> Mark

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