[QE-users] Current use of hybrid xc-functionals (PBE0/HSE)

[chris sewell]

Thanks Giuseppe,

I assume you are referring to these SG15 ONCVs; http://www.quantum-simulation.org/potentials/sg15_oncv/.
And, as you mention, Rappe et al have recently created a PBE0 PP; https://journals.aps.org/prb/abstract/10.1103/PhysRevB.97.085130, not sure how to get hold of it though?

Chris

On 15/08/2018 18:29, "users on behalf of Giuseppe Mattioli" <users-bounces at lists.quantum-espresso.org on behalf of giuseppe.mattioli at ism.cnr.it> wrote:

    Dear Chris
    EXX functionals currently work very well in QE. Recent versions  
    implement the automatically compressed exchange algorithm as a default  
    solver for exx which speeds up the job. Please play also around with  
    two very useful keys such as ecutfock (cutoff for Fock density,  
    ecutfock=ecutwfc is very fast, ecutfock=2*ecutwfc is very accurate)  
    and adaptive_thresh (sorry if it is misspelled, I’m quoting by  
    hearth), which lowers the wfc threshold of inner scf cycles far from  
    convergence. However, this nice report holds in my (quite large)  
    experience only if you use norm conserving pseudopotentials: the  
    calculation is more stable and also faster (density cutoff is quite a  
    bottleneck). ONCV PPs may be a nice starting point, but you must stick  
    to PBE. An implementation of native EXX PPs would be a very good  
    improvement. AFAIK, there is an experimental implementation in the  
    generation of PBE0 PPs in OPIUM, but I have never tested it.
    HTH
    Giuseppe
    
    
    chris sewell <chrisj_sewell at hotmail.com> ha scritto:
    
    > I’m well versed in the theory of PBE0 and HSE06 (having used them in  
    > the CRYSTAL code), but to implement in QE (and plane-wave codes in  
    > general) is there any additional considerations?
    >
    > As far as I understand, there is currently no pseudopotentials  
    > specifically available for HSE/PBE0?
    >
    > Can I then simply use my setup for PBE+PAW, with for example this  
    > pseudopotential; Fe.pbe-spn-kjpaw_psl.0.2.1.UPF, and add the option:  
    > input_dft='HSE' (and optionally set the alpha and screening  
    > parameters)?
    >
    > I hope this is not a repeat of a previous question, but the only  
    > information I could find was in a 2010 post;  
    > http://lists.quantum-espresso.org/pipermail/users/2010-May/016986.html
    >
    > Kind Regards,
    > Chris
    
    
    GIUSEPPE MATTIOLI
    CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
    Via Salaria Km 29,300 - C.P. 10
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    Mob (*preferred*) +39 373 7305625
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    E-mail: <giuseppe.mattioli at ism.cnr.it>
    
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