<div dir="ltr">Hello,<div><br></div><div>Thank you so much for your answer. Do you think it's going to converge if I use the PAW pseudopotential from the quantum espresso library, instead of the ultrasoft one?</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 19 Jun 2020 at 05:26, Mattia Angeli <<a href="mailto:mangeli@sissa.it">mangeli@sissa.it</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">Il 2020-06-19 10:15 Andrea Urru ha scritto:<br>
> Dear Coralie,<br>
> <br>
> the issue you are facing is most likely due to the W pseudopotential,<br>
> which gives convergence issues if used in slab systems<br>
> with vacuum space, as reported here:<br>
> <a href="https://dalcorso.github.io/pslibrary/PP_list.html" rel="noreferrer" target="_blank">https://dalcorso.github.io/pslibrary/PP_list.html</a><br>
> <br>
> The behavior you describe might be due to a ghost state, but I am not<br>
> deeply expert in pseudopotentials and I cannot swear.<br>
> I would suggest you to try a different pseudopotential. If you wish to<br>
> use Ultrasoft pseudopotentials you may try the one from<br>
> Pslibrary 0.3.1.<br>
> <br>
> Best regards,<br>
> <br>
> Andrea Urru<br>
> <br>
> Ph. D. Student in Condensed Matter<br>
> SISSA - Trieste (Italy)<br>
> <br>
>> Il giorno 17 giu 2020, alle ore 23:31, Coralie Khabbaz<br>
>> <<a href="mailto:khabbaz.coralie@gmail.com" target="_blank">khabbaz.coralie@gmail.com</a>> ha scritto:<br>
>> <br>
>> Hello,<br>
>> <br>
>> I am doing an scf calculation on a tungsten nitride (WN) slab<br>
>> (catalyst), with a methane molecule 5 Angstrom away from the<br>
>> surface. The energy values are not converging, even after 533<br>
>> iterations. The energy values are very negative, and then they<br>
>> increase to a positive value then decrease a lot again. Before<br>
>> building the supercell, I had a WN unit cell with 433 K-points.<br>
>> Then, I built the super cell by using a scaling of 333 and miller<br>
>> indices of 100. I tried using K points of 111 and 222 for my super<br>
>> cell, but the calculations didn't converge for both.<br>
>> <br>
>> This is the input file I am using:<br>
>> <br>
>> &CONTROL<br>
>> calculation = "scf"<br>
>> max_seconds = 1.72800e+05<br>
>> pseudo_dir =<br>
>> "/home/coralee/projects/def-jkopysci/coralee/.pseudopot"<br>
>> restart_mode = "from_scratch"<br>
>> /<br>
>> <br>
>> &SYSTEM<br>
>> a = 1.24907e+01<br>
>> angle1(1) = 0.00000e+00<br>
>> angle1(2) = 0.00000e+00<br>
>> angle2(1) = 0.00000e+00<br>
>> angle2(2) = 0.00000e+00<br>
>> b = 1.34803e+01<br>
>> c = 2.52767e+01<br>
>> cosab = 6.12323e-17<br>
>> cosac = 6.12323e-17<br>
>> cosbc = -1.85547e-01<br>
>> degauss = 1.00000e-02<br>
>> ecutrho = 4.50000e+02<br>
>> ecutwfc = 5.00000e+01<br>
>> ibrav = 14<br>
>> nat = 113<br>
>> nspin = 2<br>
>> ntyp = 4<br>
>> occupations = "smearing"<br>
>> smearing = "gaussian"<br>
>> starting_magnetization(1) = 2.00000e-01<br>
>> starting_magnetization(2) = 6.00000e-01<br>
>> starting_magnetization(3) = 0.00000e+00<br>
>> starting_magnetization(4) = 0.00000e+00<br>
>> /<br>
>> <br>
>> &ELECTRONS<br>
>> conv_thr = 1.00000e-06<br>
>> diagonalization = "david"<br>
>> electron_maxstep = 528<br>
>> mixing_beta = 4.00000e-01<br>
>> startingpot = "atomic"<br>
>> startingwfc = "atomic+random"<br>
>> /<br>
>> <br>
>> K_POINTS {automatic}<br>
>> 4 4 2 0 0 0<br>
>> <br>
>> ATOMIC_SPECIES<br>
>> N 14.00674 N.pbe-n-rrkjus_psl.1.0.0.UPF<br>
>> W 183.84000 W.pbe-spn-rrkjus_psl.1.0.0.UPF<br>
>> C 12.01070 C.pbe-n-rrkjus_psl.1.0.0.UPF<br>
>> H 1.00794 H.pbe-rrkjus_psl.1.0.0.UPF<br>
>> <br>
>> ATOMIC_POSITIONS {angstrom}<br>
>> N 2.481849 0.418242 14.837784<br>
>> N 6.645429 0.418242 14.837784<br>
>> N 10.809008 0.418242 14.837784<br>
>> N 2.481849 4.911686 14.837784<br>
>> N 6.645429 4.911686 14.837784<br>
>> N 10.809008 4.911686 14.837784<br>
>> N 2.481849 9.405131 14.837784<br>
>> N 6.645429 9.405131 14.837784<br>
>> N 10.809008 9.405131 14.837784<br>
>> W 2.481849 2.628097 14.748648<br>
>> W 6.645429 2.628097 14.748648<br>
>> W 10.809008 2.628097 14.748648<br>
>> W 2.481849 7.121541 14.748648<br>
>> W 6.645429 7.121541 14.748648<br>
>> W 10.809008 7.121541 14.748648<br>
>> W 2.481849 -1.865347 14.748648<br>
>> W 6.645429 -1.865347 14.748648<br>
>> W 10.809008 -1.865347 14.748648<br>
>> N 0.400059 3.110895 14.468179<br>
>> N 4.563639 3.110895 14.468179<br>
>> N 8.727218 3.110895 14.468179<br>
>> N 0.400059 7.604339 14.468179<br>
>> N 4.563639 7.604339 14.468179<br>
>> N 8.727218 7.604339 14.468179<br>
>> N 0.400059 -1.382549 14.468179<br>
>> N 4.563639 -1.382549 14.468179<br>
>> N 8.727218 -1.382549 14.468179<br>
>> W 0.400059 0.783425 14.415413<br>
>> W 4.563639 0.783425 14.415413<br>
>> W 8.727218 0.783425 14.415413<br>
>> W 0.400059 5.276869 14.415413<br>
>> W 4.563639 5.276869 14.415413<br>
>> W 8.727218 5.276869 14.415413<br>
>> W 0.400059 9.770314 14.415413<br>
>> W 4.563639 9.770314 14.415413<br>
>> W 8.727218 9.770314 14.415413<br>
>> N 2.481849 3.081849 12.630078 0 0 0<br>
>> N 6.645429 3.081849 12.630078 0 0 0<br>
>> N 10.809008 3.081849 12.630078 0 0 0<br>
>> N 2.481849 7.575293 12.630078 0 0 0<br>
>> N 6.645429 7.575293 12.630078 0 0 0<br>
>> N 10.809008 7.575293 12.630078 0 0 0<br>
>> N 2.481849 -1.411595 12.630078 0 0 0<br>
>> N 6.645429 -1.411595 12.630078 0 0 0<br>
>> N 10.809008 -1.411595 12.630078 0 0 0<br>
>> W 2.481849 0.798260 12.540942 0 0 0<br>
>> W 6.645429 0.798260 12.540942 0 0 0<br>
>> W 10.809008 0.798260 12.540942 0 0 0<br>
>> W 2.481849 5.291704 12.540942 0 0 0<br>
>> W 6.645429 5.291704 12.540942 0 0 0<br>
>> W 10.809008 5.291704 12.540942 0 0 0<br>
>> W 2.481849 9.785148 12.540942 0 0 0<br>
>> W 6.645429 9.785148 12.540942 0 0 0<br>
>> W 10.809008 9.785148 12.540942 0 0 0<br>
>> N 0.400059 1.281057 12.260473 0 0 0<br>
>> N 4.563639 1.281057 12.260473 0 0 0<br>
>> N 8.727218 1.281057 12.260473 0 0 0<br>
>> N 0.400059 5.774502 12.260473 0 0 0<br>
>> N 4.563639 5.774502 12.260473 0 0 0<br>
>> N 8.727218 5.774502 12.260473 0 0 0<br>
>> N 0.400059 10.267946 12.260473 0 0 0<br>
>> N 4.563639 10.267946 12.260473 0 0 0<br>
>> N 8.727218 10.267946 12.260473 0 0 0<br>
>> W 0.400059 3.447032 12.207706 0 0 0<br>
>> W 4.563639 3.447032 12.207706 0 0 0<br>
>> W 8.727218 3.447032 12.207706 0 0 0<br>
>> W 0.400059 7.940476 12.207706 0 0 0<br>
>> W 4.563639 7.940476 12.207706 0 0 0<br>
>> W 8.727218 7.940476 12.207706 0 0 0<br>
>> W 0.400059 -1.046412 12.207706 0 0 0<br>
>> W 4.563639 -1.046412 12.207706 0 0 0<br>
>> W 8.727218 -1.046412 12.207706 0 0 0<br>
>> N 2.481849 1.252012 10.422372 0 0 0<br>
>> N 6.645429 1.252012 10.422372 0 0 0<br>
>> N 10.809008 1.252012 10.422372 0 0 0<br>
>> N 2.481849 5.745456 10.422372 0 0 0<br>
>> N 6.645429 5.745456 10.422372 0 0 0<br>
>> N 10.809008 5.745456 10.422372 0 0 0<br>
>> N 2.481849 10.238900 10.422372 0 0 0<br>
>> N 6.645429 10.238900 10.422372 0 0 0<br>
>> N 10.809008 10.238900 10.422372 0 0 0<br>
>> W 2.481849 3.461867 10.333236 0 0 0<br>
>> W 6.645429 3.461867 10.333236 0 0 0<br>
>> W 10.809008 3.461867 10.333236 0 0 0<br>
>> W 2.481849 7.955311 10.333236 0 0 0<br>
>> W 6.645429 7.955311 10.333236 0 0 0<br>
>> W 10.809008 7.955311 10.333236 0 0 0<br>
>> W 2.481849 -1.031577 10.333236 0 0 0<br>
>> W 6.645429 -1.031577 10.333236 0 0 0<br>
>> W 10.809008 -1.031577 10.333236 0 0 0<br>
>> N 0.400059 3.944664 10.052766 0 0 0<br>
>> N 4.563639 3.944664 10.052766 0 0 0<br>
>> N 8.727218 3.944664 10.052766 0 0 0<br>
>> N 0.400059 8.438108 10.052766 0 0 0<br>
>> N 4.563639 8.438108 10.052766 0 0 0<br>
>> N 8.727218 8.438108 10.052766 0 0 0<br>
>> N 0.400059 -0.548780 10.052766 0 0 0<br>
>> N 4.563639 -0.548780 10.052766 0 0 0<br>
>> N 8.727218 -0.548780 10.052766 0 0 0<br>
>> W 0.400059 1.617195 10.000000 0 0 0<br>
>> W 4.563639 1.617195 10.000000 0 0 0<br>
>> W 8.727218 1.617195 10.000000 0 0 0<br>
>> W 0.400059 6.110639 10.000000 0 0 0<br>
>> W 4.563639 6.110639 10.000000 0 0 0<br>
>> W 8.727218 6.110639 10.000000 0 0 0<br>
>> W 0.400059 10.604083 10.000000 0 0 0<br>
>> W 4.563639 10.604083 10.000000 0 0 0<br>
>> W 8.727218 10.604083 10.000000 0 0 0<br>
>> C 10.809008 2.628097 19.750000<br>
>> H 10.177000 1.997000 20.383000<br>
>> H 11.443000 1.997000 19.117000<br>
>> H 10.177000 3.263000 19.117000<br>
>> H 11.443000 3.263000 20.383000<br>
>> <br>
>> _______________________________________________<br>
>> Quantum ESPRESSO is supported by MaX<br>
>> (<a href="http://www.max-centre.eu/quantum-espresso" rel="noreferrer" target="_blank">www.max-centre.eu/quantum-espresso</a> [1])<br>
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> <br>
> <br>
> <br>
> Links:<br>
> ------<br>
> [1] <a href="http://www.max-centre.eu/quantum-espresso" rel="noreferrer" target="_blank">http://www.max-centre.eu/quantum-espresso</a><br>
> _______________________________________________<br>
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<br>
<br>
Dear All,<br>
<br>
As Andrea mentioned before, the PBE-ultrasoft pseudos for W found in <br>
PSlibrary 1.0.0 are not working for 2D geometries.<br>
However, I had similar convergence issues also using W pseudos taken <br>
from older versions of PSlibrary (both scalar and fully relativistic), <br>
especially if lattice relaxation was included in the calculation.<br>
<br>
I solved the problem by using the pseudopotentials found here: <br>
<a href="https://www.materialscloud.org/discover/sssp/table/efficiency" rel="noreferrer" target="_blank">https://www.materialscloud.org/discover/sssp/table/efficiency</a><br>
<br>
best,<br>
<br>
<br>
<br>
<br>
Mattia Angeli<br>
<br>
Ph. D. Student in Condensed Matter<br>
SISSA - Trieste (Italy)<br>
<br>
<br>
<br>
_______________________________________________<br>
Quantum ESPRESSO is supported by MaX (<a href="http://www.max-centre.eu/quantum-espresso" rel="noreferrer" target="_blank">www.max-centre.eu/quantum-espresso</a>)<br>
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</blockquote></div>