[DFTB-Plus-User] iterated process of MD jobs

[Bálint Aradi]

Dear Young,

> 1. The xyz format of DFTB+ has seven columns, that is, seven attributes
> per atom.
> 
> I suppose that the first three are for postion ans the last three are
> for velocity. Then, what does fourth column represent? 

Charge of the given atom.

> 2. For NPT simulation, three lattice constants should be stored at every
> MDRestartFrequency. Then, are these values additionally stored in the
> xyz file, compared to that of NVT ensemble?

No, because the XYZ-file unfortunately does not offer a standard way to
store lattice vector information.

> 3. I'd like to know xx,yy,zz component (or -Pxx, -Pyy, -Pzz) of stress
> tensor. How can I know these values using DFTB+?

When the stress tensor is calculated, those values are written in the
detailed.out file, so you can extract from there the last calculated value.

If you wanted to have the value for each geometry during the MD, you
would have to modify the writeMdOut2() routine in order to add it to
md.out. The relevant lines in the code were:

https://github.com/dftbplus/dftbplus/blob/dfb2b71412e91cd6e49edca6a07012ab155d108e/prog/dftb%2B/lib_dftbplus/mainio.F90#L3191

and

https://github.com/dftbplus/dftbplus/blob/dfb2b71412e91cd6e49edca6a07012ab155d108e/prog/dftb%2B/lib_dftbplus/main.F90#L931

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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