Geometry optimization convergence problem

Peter pmam... at gmail.com
Tue Mar 17 17:51:18 UTC 2009


Thank you for reply, Teodoro!

>The limit you have reached of 2e-3 Hartree/bohr is not bad at all (is in
>the order of ~ 3 kcal/angstrom).

I made some estimations (once again :) ), and now I see that it's
probably ok for my problem, (taking into account small RMS gradient
values). So, sorry for bothering you.

Concerning your second remark:

> The above section (POISSON) makes no sense since you don't ask for any
> specific kind of EWALD (so this
> means that the Coulomb interactions are computed by pair 1/r using the
> cutoff of the NB interactions) in addition with
> a WAVELET solver.

Well, I don't ask for an Ewald summation, since I consider an isolated
system. I want only interactions between explicitly defined particles.
Since only pair nonbonded interactions are considered - no need to
solve Poisson eq.. So should I just omit PSOLVER?

P.S. Actually this calculation is a preparation for a QM/MM run.

On Mar 17, 6:39 pm, Teodoro Laino <teodor... at gmail.com> wrote:
> Dear Peter,
> an additional remark on your input file:
>
> >     &POISSON
> >       PERIODIC NONE
> >       PSOLVER WAVELET
> >       &EWALD
> >         EWALD_TYPE NONE
> >       &END EWALD
> >     &END POISSON
>
> The above section (POISSON) makes no sense since you don't ask for any
> specific kind of EWALD (so this
> means that the Coulomb interactions are computed by pair 1/r using the
> cutoff of the NB interactions) in addition with
> a WAVELET solver.
> If you want full electrostatic you need to choose a proper EWALD_TYPE.
> Keep in mind that none of the decoupling techniques (either MT or
> WAVELET or others) work in conjuction
> with MM FF. With classical run you must do everything fully periodic.
>
> Cheers
> Teo


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