[QE-users] CASTEP to QE setup parameters conversions

[Husak Michal]

Dear Nicola Marzari


I had already done everything you suggest + more:

1) Converted my structures by the Material Cloud convertor

2) Converted my structures by BURAI GUI

3)Semi/manually converted my structures from CIF to QE by the help of QE

internal Space Group Handling

4) Read multiple articles optimizing QE parameters exactly for the same problem I investigate (organic molecular crystals)

+ tested the parameters they use (e.g. https://pubs.acs.org/doi/10.1021/cg4002797 )


I know how to process my data in QE ..

I search for maximally exact CASTEP/QE calculations setup replication,

to be able to check performance/result of both codes ...

I had already made huge  number of calculations in CASTEP optimizing the setup/performance ..

So I ask how to set QE identically as CASTEP as much as possible ...





________________________________
From: Nicola Marzari <nicola.marzari at gmail.com>
Sent: Saturday, November 14, 2020 8:22:48 PM
To: Quantum ESPRESSO users Forum; Husak Michal
Subject: Re: [QE-users] CASTEP to QE setup parameters conversions


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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