[QE-users] Can we calculate pressure from just relaxation result?

[Lorenzo Paulatto]

If you want to have the pressure you need to set tstress=.true. in the 
control namelist

regards

On 9/17/19 2:14 AM, Yeon, Jejoon wrote:
> Hello
> 
> I have some relaxation (not vc-relax) output files of the same unit 
> cell, but with different volume.
> 
> I used fractional coordinates (= crystal coordinates) and just slightly 
> modified the cell parameters to compress / expand the volume, to 
> calculate potential energy at given fixed volume conditions.
> 
> I know vc-relax prints out pressure value, but it seems they are not in 
> normal relaxation.
> 
> I thought that there will be pressure output in the QE output file, but 
> I can't find any pressure or stress data in output file of relaxation.
> 
> Is there any analytical or other ways to calculate pressure (or pressure 
> component of x, y, and z direction) of unit cell (thermodynamic 
> pressure) from relaxation output file?
> 
> Or do I need to calculate using vc-relax again, to find the 
> corresponding pressure for given fixed volume conditions?
> 
> Thanks
> 
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
> 

-- 
Lorenzo Paulatto - Paris