[Pw_forum] maybe a bug in the QE 4.0.4 (Stefano Baroni)

[hanghui chen]

Yes. At vanish electric field, even with USPP the stress is the same as the
normal calculation (without using Berry Phase method).
Hope this helps.

Is your calculated stress OK with USPP at vaishing electric field?
SB

On Apr 1, 2009, at 4:48 PM, hanghui chen wrote:

> Dear PWscf developers and in particular Professor Baroni,
>       Thank you very much for your instructions.
>       I did the test to check the forces and stress in the Berry
> phase method with the ultrasoft pseudopotential. The forces are
> correct but the stress is around 50% smaller. I am not sure whether
> it is due to the ultrasoft pseudopotential or not.
>       I would greatly appreciate it if the developers of QE could
> reexamine the calculation of stress in the Berry phase method with
> the ultrasoft pseudopotential.
>       Best wishes.
>
> Hanghui Chen
> Department of Physics,
> Yale University
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