[DFTB-Plus-User] Fragmented optimized structure

[Alessandro LANDI]

Dear Balint,



*Can it be, that your starting geometry is not folded into the central
cell? DFTB+ foolds the cell by ensuring, that all coordinates are between 0
and 1*

thank you for the suggestion, you are probably right. Since I am starting
from a xyz unit cell obtained by Mercury software (CSD suite), I have some
negative coordinates in the starting geometry.
I will try using "ShowFoldedCoords       =       No" as suggested

Best regards,
Alessandro

Il giorno gio 7 mag 2020 alle ore 10:10 Bálint Aradi via DFTB-Plus-User <
dftb-plus-user at mailman.zfn.uni-bremen.de> ha scritto:

> Dear Alessandro,
>
> > if you read the input file that I provided at the end of my previous
> > e-mail, you will notice that I already have included
> >
> > Options {
> >   ShowFoldedCoords       =       Yes
> > }
>
> Sorry, I've overlooked that. Can it be, that your starting geometry is
> not folded into the central cell? DFTB+ foolds the cell by ensuring,
> that all coordinates are between 0 and 1 (if you convert the absolute
> cartesian coordinates into fractional ones). If your starting system
> does not satisfy this condition, the first folding will move the atoms.
>
> But actually, probably setting ShowFoldedCoords to No would be what you
> are actually looking for. Then, DFTB+ won't fold anything, so the
> absolute coordinates should remain close to the original ones (provided
> the relaxation is not big).
>
> Best regards,
>
> Bálint
>
> --
> Dr. Bálint Aradi
> Bremen Center for Computational Materials Science, University of Bremen
> http://www.bccms.uni-bremen.de/cms/people/b-aradi/
>
>
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-- 
Alessandro Landi, Assegnista di Ricerca
Dipartimento di Chimica e Biologia "Adolfo Zambelli"
Università degli Studi di Salerno
Via Giovanni Paolo II, 132 - 84084 - Fisciano (SA)
Phone number 089969390
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