[QE-users] [SPAM] Convergence issue in spin-polarized SCAN calculation

[Nicola Marzari]

Hi Michal,


these are two different problems - lack of convergence is not driven by 
pseudopotentials, but by algorithms. CASTEP uses a variational 
minimization, that is bound to converge, but tends to be slower - QE is 
iterative. Changing pseudopotentials might randomly make your 
calculations converge.

Generation of pseudopotential on the fly - well, you'll never know if 
they have ghost states, or how accurate they are - it's a highly 
non-linear problem.

nciola



On 25/12/2023 14:59, Husak Michal via users wrote:
> Hi
> 
> 
> I apology to QE users, but my solution:
> 
> Use instead of QE CASTEP, witch generates pseudopotentials on the fly
> 
> optimized for given functional (no databases used) ... It solves all the pseudopotential database issues ..
> 
> Supports rSCAN, r2SCAN ...
> 
> 
> I hope QE authors will sometime add to the PW the on-the fly pseudopotential generation
> 
> functionality with no need to have external files  ...
> 
> 
> Michal Husak
> 
> UCT Prague
> 
> 
> ________________________________
> From: users <users-bounces at lists.quantum-espresso.org> on behalf of Jing Lian Ng <jinglian at utexas.edu>
> Sent: Monday, December 25, 2023 2:51 PM
> To: users at lists.quantum-espresso.org
> Subject: [SPAM] [QE-users] Convergence issue in spin-polarized SCAN calculation
> 
> Hello all,
> 
> I am performing spin polarized calculation with SCAN functional on nickel oxyhydroxide system (NiOOH) and ran into convergence issue in my SCF calculation. Dr Yi-Min Ding reported a similar issue (https://lists.quantum-espresso.org/pipermail/users/2023-March/050277.html) and someone suggested that the issue could be due to the pseudos have been generated with PBE and then used with the SCAN functional. I tested NCPP from PseudoDojo library and SG15 library, both resulted in convergence issues when spin-polarized calculation is enabled. I have include the link for NCPP files from both libraries below, any advice would be appreciated.
> 
> NCPP for Ni, O and H:
> PseudoDojo: http://www.pseudo-dojo.org/
> SG15: http://quantum-simulation.org/potentials/sg15_oncv/
> 
> Thank you,
> Jing Lian Ng
> 2nd Year PhD Student at University of Texas
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-- 
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, SNSF
Head, Laboratory for Materials Simulations, Paul Scherrer Institut
Contact info and websites at http://theossrv1.epfl.ch/Main/Contact