<div dir="ltr"><div><div><div><div>Dear Giuseppe,<br><br></div>I had tried the calculations with higher ecutwfc before and as you said it perfectly worked. But the problem is that the calculations take much longer. Is there any way to keep the ecutwfc as small as possible and use different pseudopotentials and still get convergence? Please advise.<br><br></div>Many thanks in advance.<br><br></div>Regards,<br></div>Reza<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Jun 11, 2016 at 2:21 PM, Giuseppe Mattioli <span dir="ltr"><<a href="mailto:giuseppe.mattioli@ism.cnr.it" target="_blank">giuseppe.mattioli@ism.cnr.it</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Dear Reza Vatan<br>
<br>
> ecutwfc = 12.0,<br>
<span class=""><br>
> Ga 69.72 Ga.blyp-d-hgh.UPF<br>
> P 30.97 P.blyp-hgh.UPF<br>
<br>
</span>It is very strange that you converge at all with a so minimal cutoff<br>
and so hard hgh norm-conserving pseudopotentials. I would bet that<br>
ecutwfc = 100.0 is barely sufficient for Ga with semicore d shell in<br>
valence. I suggest that you raise ecutwfc and find convergence for GaP<br>
in the 2 atoms cell.<br>
HTH<br>
Giuseppe<br>
<div><div class="h5"><br>
Quoting reza vatan <<a href="mailto:rezavatan64@gmail.com">rezavatan64@gmail.com</a>>:<br>
<br>
> Dear all,<br>
><br>
> I'm trying to optimize the atomic structure of GaP using QE. When I use a<br>
> unit cell only containing two atoms, I have no problem in SCF convergence<br>
> and the structure get optimized in the first step. But when I make my unit<br>
> cell bigger (let's say a unit cell with 64 atoms) just by repeating my<br>
> smaller optimized unit cell in real space and run relax calculation, the<br>
> SCF calculation never get converged. Does anyone know where the problem is?<br>
><br>
> Following is my input:<br>
><br>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br>
> &CONTROL<br>
> calculation = "relax",<br>
> dt = 30.D0,<br>
> prefix = 'gap',<br>
> pseudo_dir = './',<br>
> outdir='./',<br>
> /<br>
> &system<br>
> ibrav= 6, celldm(1) =20.52, celldm(3) =1, nat= 64, ntyp= 2,<br>
> ecutwfc = 12.0,<br>
> degauss = 0.05D0,<br>
> occupations = "fixed",<br>
> smearing = "methfessel-paxton",<br>
> /<br>
> &ELECTRONS<br>
> conv_thr = 1.D-7,<br>
> mixing_beta = 0.3D0,<br>
> electron_maxstep= 200,<br>
> /<br>
> &IONS<br>
> pot_extrapolation = "second_order",<br>
> wfc_extrapolation = "second_order",<br>
> /<br>
> ATOMIC_SPECIES<br>
> Ga 69.72 Ga.blyp-d-hgh.UPF<br>
> P 30.97 P.blyp-hgh.UPF<br>
> ATOMIC_POSITIONS (angstrom)<br>
> Ga 2.7146780000 2.7146780000 0.0000000000<br>
> Ga 0.0000000000 0.0000000000 0.0000000000<br>
> Ga 2.7146780000 0.0000000000 2.7146780000<br>
> Ga 0.0000000000 2.7146780000 2.7146780000<br>
> P 4.0720170000 4.0720170000 1.3573390000<br>
> P 1.3573390000 1.3573390000 1.3573390000<br>
> P 4.0720170000 1.3573390000 4.0720170000<br>
> P 1.3573390000 4.0720170000 4.0720170000<br>
> Ga 2.7146780000 2.7146780000 5.4293560000<br>
> Ga 0.0000000000 0.0000000000 5.4293560000<br>
> Ga 2.7146780000 0.0000000000 8.1440340000<br>
> Ga 0.0000000000 2.7146780000 8.1440340000<br>
> P 4.0720170000 4.0720170000 6.7866950000<br>
> P 1.3573390000 1.3573390000 6.7866950000<br>
> P 4.0720170000 1.3573390000 9.5013730000<br>
> P 1.3573390000 4.0720170000 9.5013730000<br>
> Ga 2.7146780000 8.1440340000 0.0000000000<br>
> Ga 0.0000000000 5.4293560000 0.0000000000<br>
> Ga 2.7146780000 5.4293560000 2.7146780000<br>
> Ga 0.0000000000 8.1440340000 2.7146780000<br>
> P 4.0720170000 9.5013730000 1.3573390000<br>
> P 1.3573390000 6.7866950000 1.3573390000<br>
> P 4.0720170000 6.7866950000 4.0720170000<br>
> P 1.3573390000 9.5013730000 4.0720170000<br>
> Ga 2.7146780000 8.1440340000 5.4293560000<br>
> Ga 0.0000000000 5.4293560000 5.4293560000<br>
> Ga 2.7146780000 5.4293560000 8.1440340000<br>
> Ga 0.0000000000 8.1440340000 8.1440340000<br>
> P 4.0720170000 9.5013730000 6.7866950000<br>
> P 1.3573390000 6.7866950000 6.7866950000<br>
> P 4.0720170000 6.7866950000 9.5013730000<br>
> P 1.3573390000 9.5013730000 9.5013730000<br>
> Ga 8.1440340000 2.7146780000 0.0000000000<br>
> Ga 5.4293560000 0.0000000000 0.0000000000<br>
> Ga 8.1440340000 0.0000000000 2.7146780000<br>
> Ga 5.4293560000 2.7146780000 2.7146780000<br>
> P 9.5013730000 4.0720170000 1.3573390000<br>
> P 6.7866950000 1.3573390000 1.3573390000<br>
> P 9.5013730000 1.3573390000 4.0720170000<br>
> P 6.7866950000 4.0720170000 4.0720170000<br>
> Ga 8.1440340000 2.7146780000 5.4293560000<br>
> Ga 5.4293560000 0.0000000000 5.4293560000<br>
> Ga 8.1440340000 0.0000000000 8.1440340000<br>
> Ga 5.4293560000 2.7146780000 8.1440340000<br>
> P 9.5013730000 4.0720170000 6.7866950000<br>
> P 6.7866950000 1.3573390000 6.7866950000<br>
> P 9.5013730000 1.3573390000 9.5013730000<br>
> P 6.7866950000 4.0720170000 9.5013730000<br>
> Ga 8.1440340000 8.1440340000 0.0000000000<br>
> Ga 5.4293560000 5.4293560000 0.0000000000<br>
> Ga 8.1440340000 5.4293560000 2.7146780000<br>
> Ga 5.4293560000 8.1440340000 2.7146780000<br>
> P 9.5013730000 9.5013730000 1.3573390000<br>
> P 6.7866950000 6.7866950000 1.3573390000<br>
> P 9.5013730000 6.7866950000 4.0720170000<br>
> P 6.7866950000 9.5013730000 4.0720170000<br>
> Ga 8.1440340000 8.1440340000 5.4293560000<br>
> Ga 5.4293560000 5.4293560000 5.4293560000<br>
> Ga 8.1440340000 5.4293560000 8.1440340000<br>
> Ga 5.4293560000 8.1440340000 8.1440340000<br>
> P 9.5013730000 9.5013730000 6.7866950000<br>
> P 6.7866950000 6.7866950000 6.7866950000<br>
> P 9.5013730000 6.7866950000 9.5013730000<br>
> P 6.7866950000 9.5013730000 9.5013730000<br>
> K_POINTS {automatic}<br>
> 2 2 2 0 0 0<br>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br>
><br>
><br>
> Thanks in advance.<br>
><br>
> Regards,<br>
> Reza Vatan<br>
> School of Electrical, Computer and Energy Engineering<br>
> Arizona State University<br>
<br>
<br>
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