[DFTB-Plus-User] How to set the pressure at a certain direction?

[Bálint Aradi]

Dear Yecheng,

> However, the pressure in Driver only support one dimension value,
> how can I optimized the structure when I try to stretch in one
> dimension while keeping the pressure on rest directions at specified
> nonzero value, eg., stretching 20% strain in x direction while keep
> the pressure on y as 100GPa and z as 200GPa.

Currently, you can only specify the isotropic pressure in the
simulations. Although internally, we work with the full stress tensor,
the user interface currently only allows a scalar value.

> Ps. How is the pressure of simulation box related to the stress
> tensor?

The diagonal components of the stress tensor would be set to the
external pressure values provided by the user, see

https://github.com/dftbplus/dftbplus/blob/ed9ff63f15fa74fe899c8d4e77d73f44299b2b1f/prog/dftb%2B/lib_md/velocityverlet.F90#L208

  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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