Re: [AMBER] Force-field with only Bond parameters

From: Carlos Simmerling <carlos.simmerling.gmail.com>
Date: Thu, 21 Nov 2019 05:12:33 -0500

For dihedrals you should not get errors, only warnings. Are you sure they
are errors thet cause leap to stop?

On Thu, Nov 21, 2019, 5:05 AM Stefano Motta <stefano.motta.unimib.it> wrote:

> Hello,
>
> I'm trying to use a force-field for TiO2, with only electrostatic, VdW, and
> bond terms. I decided to create a mol2 file for the TiO2 nanoparticle (NP)
> and treat the NP as a whole residue (the charges for the NP atoms are in
> the mol2 file with the connectivity). Then I created an frcmod that
> contains the mass, bonded and VdW parameters.
>
> Anyway it seems that tleap is also searching for angle and dihedral term
> (that I don't want to include) and gives me error. Then I included the
> ANGLE and DIHE terms (putting them to 0) in the frcmod (all the missing
> parameters):
> For example in case of angle, a lot of lines like this:
> Ti6-Ot3-Ti6 0.0 0.0
> and in case of dihedral, a lot of lines like this:
> Ti6-Ot3-Ti6-Ot3 1 0.0 0.0 2.0
>
> Covering all the possible combinations of Angle and dihedrals.
> This resolved the problem for angle (tleap is not complaining about missing
> parameters for angles) but not for dihedrals (I still get errors even for
> dihedrals terms that I have inserted in the frcmod).
>
> How can I solve this issue? Is there a way to disable the search for angle
> and dihedral terms for this molecule?
>
> Thanks in advance
> Best,
> Stefano
>
>
>
> --
> ________________________________________________________________
>
> Stefano Motta PhD
>
> Email: stefano.motta.unimib.it <s.motta17.campus.unimib.it>
> *Field of study:* Molecular Modeling, and Proteins Molecular Dynamics
>
> Università degli Studi di Milano Bicocca
> Department of Earth and Environmental Sciences
>
> Piazza dell'Ateneo Nuovo, 1 - 20126, Milano (Italy).
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Received on Thu Nov 21 2019 - 02:30:02 PST
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