[gmx-users] QM/MM optimization in gromacs/gaussian

[Groenhof, Gerrit]

Hi,

Could the rupture suggest that perhaps the underlying QM/MM model is somewhat flawed?

What happens when you run the minimisation without the constraint between the QM and MM atoms? Do you have convergence problems?

Gerrit




Message: 2
Date: Fri, 2 Mar 2018 13:01:09 +0300
From: nikolaev at spbau.ru
To: gmx-users at gromacs.org
Subject: Re: [gmx-users] QM/MM optimization in gromacs/gaussian
        (nikolaev at spbau.ru)
Message-ID: <40fa81b002d9ded18e6f471f19a1ada7.squirrel at mail.spbau.ru>
Content-Type: text/plain;charset=UTF-8

And which one (and with what parameters) is better for the QM/MM
optimization?

Steep almost didn't change anything and I couldn't relax the system as I
wanted.
CG seemed to work fine, but in the end it teared an H-atom from my QM
subsystem.
BFGS could not work with the constraints which are necessary for the QM/MM
calculations in gromacs...




>
> Hi,
>
> It is possible, but only using gromacs' internal optizers: SD(steep), CG,
> or BFGS.
> And you can only optimise minima, not transition states.
>
> Best,
> Gerrit
>
>
>
>
>
>
>
> Message: 3
> Date: Thu, 1 Mar 2018 12:44:53 +0300
> From: nikolaev at spbau.ru
> To: gmx-users at gromacs.org
> Subject: [gmx-users] QM/MM optimization in gromacs/gaussian
> Message-ID: <ff117f222d3d76fdce88a36282ae90b6.squirrel at mail.spbau.ru>
> Content-Type: text/plain;charset=UTF-8
>
> Dear all!
>
> I need to perform the QM/MM optimization in the Gromacs/Gaussian
> interface. However, I know that in 2015 this was not possible.
>
> The question: is there such an opportunity nowadays (I use gromacs 5.1.2)
> and which kind of parameters I need to write in the .mdp file in order to
> obtain such an optimization?
>
> Thank you in advance,
> Dmitrii
>
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