[QE-users] CASTEP to QE setup parameters conversions

[Nicola Marzari]

One possibility would be to upload your structure (or in principle even 
your CASTEP .cell file) here:
https://www.materialscloud.org/work/tools/qeinputgenerator

This will give you fairly reliable input parameters (cutoff, sampling, 
etc...) and pseudopotentials for a scf calculation,
and then try to understand from this document
https://www.quantum-espresso.org/Doc/INPUT_PW.html
what else you need

             nicola


On 14/11/2020 20:13, Husak Michal wrote:
> Hi all
>
>
> I was working a lot with CASTEP last years ...
>
> I want to switch some my projects to  QE + do head to head comparison with CASTEP.
>
> I am confused by some selected corresponding setup parameters conversion
>
> (I had handled the rest including input formats conversion myself):
>
>
> QE: etot_conv_thr  (a.u.]
>
> CASTEP: geom_energy_tol (eV/atom)
>
> Should I simply  recalculate eV to a.u. and multiply by number of atoms in unit cell ?
>
> Why the definition in QE/CASTEP differs ?
>
>
> QE: forc_conv_thr  (a.u.)
>
> CASTEP: geom_force_tol (eV/angstrem)
>
> I have no idea how to convert this  parameter ....
>
>
> QE: non existing criteria
>
> CASTEP: geom_disp_tol (angstrem) , Maximal atom displacement during a cycle ..
>
> Sound like QE does not check this criteria ?
>
>
> QE: ecutrho (Ry), default 4 * ecutwfc
>
> CASTEP: non existing parameter
>
> Any idea why CASTEP does not use this parameter ?
>
>
> QE: conv_thr  , units not found/missing in manual, probably (a.u.) ?
>
> CASTEP: elec_energy_tol (eV/atom)
>
> Should I simply  recalculate eV to a.u. and multiply by number of atoms in unit cell ?
>
> Why the definition differs ?
>
>
> Michal Husak
>
> UCT Prague, Department of Solid State Chemistry
>
>
>
>
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