[gmx-users] Fwd: H2SO4 (H2PO4-) force field

[Ondrej Kroutil]

Hi gromacs user,
I have a favour to ask you.
Does anybody have working model of sulfuric acid and/or H2PO4- (exactly
these species with two OH groups)? I have tried to prepared one according
to various articles:

loukonen2010 - Enhancing effect of dimethylamine in sulfuric acid
nucleation in the presence of water – a computational study
canales2016 - A comparative molecular dynamics study of sulfuric and
methanesulfonic acids
ding2003 - Reliable potential for small sulfuric acid–water clusters
margreitter2017 - Update on phosphate and charged post‐translationally
modified amino acid parameters in the GROMOS force field -- dihedrals from
this study were used with Loukonen params.

but very often these models were unstable (or I should say my
implementations of these models were unstable) and after several
nanoseconds I got LINCS warning followed by a collapse of the oxoacid
structure and forced end of the simulation. I attach my implementation of
mentioned models and mdp file I use to run this simulations.

I bet the problem is connected to dihedrals O-P(S)-O-H but I'm not hundred
percent sure.

I'll be glad for every .itp file you can offer me.

Thank a lot and have a nice day.

    Ondřej Kroutil

https://scholar.google.cz/citations?user=vFX-JpoAAAAJ&hl=cs

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Ondřej Kroutil
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