[gmx-users] very small nonzero charge

Alex nedomacho at gmail.com
Thu Sep 27 11:40:00 CEST 2018

Hm, i thought it was a question someone could answer...

On Sat, Sep 22, 2018, 10:52 PM Alex <nedomacho at gmail.com> wrote:

> Hi all,
> I am dealing with a solid structure with partial charges initially
> obtained from DFT and adjusted to work with MD. It just so happens that
> the total charge of the system, however small, will always be nonzero.
> The reason is trivial and unfortunately unavoidable, given the
> geometries. It sounds silly, but this is the situation. It has to do
> with division by three and one of the partial charges will have to have
> the form of e.g. 0.333333... Hence, a few questions:
> 1. Is the total charge of the system of the order ~1e-6 expected to
> produce artifacts with the latest versions of GMX (we're using 2018.1)?
> 2. The total charge will go down with the number of digits readable by
> x2top from atomname2type, so what's the max number of digits I could
> supply?
> Thanks,
> Alex

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