<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Dear Coralie, <div class=""><br class=""></div><div class="">the issue you are facing is most likely due to the W pseudopotential, which gives convergence issues if used in slab systems </div><div class="">with vacuum space, as reported here: <a href="https://dalcorso.github.io/pslibrary/PP_list.html" class="">https://dalcorso.github.io/pslibrary/PP_list.html</a></div><div class=""><br class=""></div><div class="">The behavior you describe might be due to a ghost state, but I am not deeply expert in pseudopotentials and I cannot swear. </div><div class="">I would suggest you to try a different pseudopotential. If you wish to use Ultrasoft pseudopotentials you may try the one from </div><div class="">Pslibrary 0.3.1. </div><div class=""><br class=""></div><div class="">Best regards, </div><div class=""><br class=""></div><div class="">Andrea Urru</div><div class=""><br class=""></div><div class="">Ph. D. Student in Condensed Matter </div><div class="">SISSA - Trieste (Italy) <br class=""><div><br class=""><blockquote type="cite" class=""><div class="">Il giorno 17 giu 2020, alle ore 23:31, Coralie Khabbaz <<a href="mailto:khabbaz.coralie@gmail.com" class="">khabbaz.coralie@gmail.com</a>> ha scritto:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div dir="ltr" class="">Hello,<div class=""><br class=""></div><div class="">I am doing an scf calculation on a tungsten nitride (WN) slab (catalyst), with a methane molecule 5 Angstrom away from the surface. The energy values are not converging, even after 533 iterations. The energy values are very negative, and then they increase to a positive value then decrease a lot again. Before building the supercell, I had a WN unit cell with 433 K-points. Then, I built the super cell by using a scaling of 333 and miller indices of 100. I tried using K points of 111 and 222 for my super cell, but the calculations didn't converge for both. </div><div class=""><br class=""></div><div class="">This is the input file I am using:</div><div class=""><div class=""><br class=""></div><div class="">&CONTROL</div><div class=""> calculation = "scf"</div><div class=""> max_seconds = 1.72800e+05</div><div class=""> pseudo_dir = "/home/coralee/projects/def-jkopysci/coralee/.pseudopot"</div><div class=""> restart_mode = "from_scratch"</div><div class="">/</div><div class=""><br class=""></div><div class="">&SYSTEM</div><div class=""> a = 1.24907e+01</div><div class=""> angle1(1) = 0.00000e+00</div><div class=""> angle1(2) = 0.00000e+00</div><div class=""> angle2(1) = 0.00000e+00</div><div class=""> angle2(2) = 0.00000e+00</div><div class=""> b = 1.34803e+01</div><div class=""> c = 2.52767e+01</div><div class=""> cosab = 6.12323e-17</div><div class=""> cosac = 6.12323e-17</div><div class=""> cosbc = -1.85547e-01</div><div class=""> degauss = 1.00000e-02</div><div class=""> ecutrho = 4.50000e+02</div><div class=""> ecutwfc = 5.00000e+01</div><div class=""> ibrav = 14</div><div class=""> nat = 113</div><div class=""> nspin = 2</div><div class=""> ntyp = 4</div><div class=""> occupations = "smearing"</div><div class=""> smearing = "gaussian"</div><div class=""> starting_magnetization(1) = 2.00000e-01</div><div class=""> starting_magnetization(2) = 6.00000e-01</div><div class=""> starting_magnetization(3) = 0.00000e+00</div><div class=""> starting_magnetization(4) = 0.00000e+00</div><div class="">/</div><div class=""><br class=""></div><div class="">&ELECTRONS</div><div class=""> conv_thr = 1.00000e-06</div><div class=""> diagonalization = "david"</div><div class=""> electron_maxstep = 528</div><div class=""> mixing_beta = 4.00000e-01</div><div class=""> startingpot = "atomic"</div><div class=""> startingwfc = "atomic+random"</div><div class="">/</div><div class=""><br class=""></div><div class="">K_POINTS {automatic}</div><div class=""> 4 4 2 0 0 0</div><div class=""><br class=""></div><div class="">ATOMIC_SPECIES</div><div class="">N 14.00674 N.pbe-n-rrkjus_psl.1.0.0.UPF</div><div class="">W 183.84000 W.pbe-spn-rrkjus_psl.1.0.0.UPF</div><div class="">C 12.01070 C.pbe-n-rrkjus_psl.1.0.0.UPF</div><div class="">H 1.00794 H.pbe-rrkjus_psl.1.0.0.UPF</div><div class=""><br class=""></div><div class="">ATOMIC_POSITIONS {angstrom}</div><div class="">N 2.481849 0.418242 14.837784</div><div class="">N 6.645429 0.418242 14.837784</div><div class="">N 10.809008 0.418242 14.837784</div><div class="">N 2.481849 4.911686 14.837784</div><div class="">N 6.645429 4.911686 14.837784</div><div class="">N 10.809008 4.911686 14.837784</div><div class="">N 2.481849 9.405131 14.837784</div><div class="">N 6.645429 9.405131 14.837784</div><div class="">N 10.809008 9.405131 14.837784</div><div class="">W 2.481849 2.628097 14.748648</div><div class="">W 6.645429 2.628097 14.748648</div><div class="">W 10.809008 2.628097 14.748648</div><div class="">W 2.481849 7.121541 14.748648</div><div class="">W 6.645429 7.121541 14.748648</div><div class="">W 10.809008 7.121541 14.748648</div><div class="">W 2.481849 -1.865347 14.748648</div><div class="">W 6.645429 -1.865347 14.748648</div><div class="">W 10.809008 -1.865347 14.748648</div><div class="">N 0.400059 3.110895 14.468179</div><div class="">N 4.563639 3.110895 14.468179</div><div class="">N 8.727218 3.110895 14.468179</div><div class="">N 0.400059 7.604339 14.468179</div><div class="">N 4.563639 7.604339 14.468179</div><div class="">N 8.727218 7.604339 14.468179</div><div class="">N 0.400059 -1.382549 14.468179</div><div class="">N 4.563639 -1.382549 14.468179</div><div class="">N 8.727218 -1.382549 14.468179</div><div class="">W 0.400059 0.783425 14.415413</div><div class="">W 4.563639 0.783425 14.415413</div><div class="">W 8.727218 0.783425 14.415413</div><div class="">W 0.400059 5.276869 14.415413</div><div class="">W 4.563639 5.276869 14.415413</div><div class="">W 8.727218 5.276869 14.415413</div><div class="">W 0.400059 9.770314 14.415413</div><div class="">W 4.563639 9.770314 14.415413</div><div class="">W 8.727218 9.770314 14.415413</div><div class="">N 2.481849 3.081849 12.630078 0 0 0</div><div class="">N 6.645429 3.081849 12.630078 0 0 0</div><div class="">N 10.809008 3.081849 12.630078 0 0 0</div><div class="">N 2.481849 7.575293 12.630078 0 0 0</div><div class="">N 6.645429 7.575293 12.630078 0 0 0</div><div class="">N 10.809008 7.575293 12.630078 0 0 0</div><div class="">N 2.481849 -1.411595 12.630078 0 0 0</div><div class="">N 6.645429 -1.411595 12.630078 0 0 0</div><div class="">N 10.809008 -1.411595 12.630078 0 0 0</div><div class="">W 2.481849 0.798260 12.540942 0 0 0</div><div class="">W 6.645429 0.798260 12.540942 0 0 0</div><div class="">W 10.809008 0.798260 12.540942 0 0 0</div><div class="">W 2.481849 5.291704 12.540942 0 0 0</div><div class="">W 6.645429 5.291704 12.540942 0 0 0</div><div class="">W 10.809008 5.291704 12.540942 0 0 0</div><div class="">W 2.481849 9.785148 12.540942 0 0 0</div><div class="">W 6.645429 9.785148 12.540942 0 0 0</div><div class="">W 10.809008 9.785148 12.540942 0 0 0</div><div class="">N 0.400059 1.281057 12.260473 0 0 0</div><div class="">N 4.563639 1.281057 12.260473 0 0 0</div><div class="">N 8.727218 1.281057 12.260473 0 0 0</div><div class="">N 0.400059 5.774502 12.260473 0 0 0</div><div class="">N 4.563639 5.774502 12.260473 0 0 0</div><div class="">N 8.727218 5.774502 12.260473 0 0 0</div><div class="">N 0.400059 10.267946 12.260473 0 0 0</div><div class="">N 4.563639 10.267946 12.260473 0 0 0</div><div class="">N 8.727218 10.267946 12.260473 0 0 0</div><div class="">W 0.400059 3.447032 12.207706 0 0 0</div><div class="">W 4.563639 3.447032 12.207706 0 0 0</div><div class="">W 8.727218 3.447032 12.207706 0 0 0</div><div class="">W 0.400059 7.940476 12.207706 0 0 0</div><div class="">W 4.563639 7.940476 12.207706 0 0 0</div><div class="">W 8.727218 7.940476 12.207706 0 0 0</div><div class="">W 0.400059 -1.046412 12.207706 0 0 0</div><div class="">W 4.563639 -1.046412 12.207706 0 0 0</div><div class="">W 8.727218 -1.046412 12.207706 0 0 0</div><div class="">N 2.481849 1.252012 10.422372 0 0 0</div><div class="">N 6.645429 1.252012 10.422372 0 0 0</div><div class="">N 10.809008 1.252012 10.422372 0 0 0</div><div class="">N 2.481849 5.745456 10.422372 0 0 0</div><div class="">N 6.645429 5.745456 10.422372 0 0 0</div><div class="">N 10.809008 5.745456 10.422372 0 0 0</div><div class="">N 2.481849 10.238900 10.422372 0 0 0</div><div class="">N 6.645429 10.238900 10.422372 0 0 0</div><div class="">N 10.809008 10.238900 10.422372 0 0 0</div><div class="">W 2.481849 3.461867 10.333236 0 0 0</div><div class="">W 6.645429 3.461867 10.333236 0 0 0</div><div class="">W 10.809008 3.461867 10.333236 0 0 0</div><div class="">W 2.481849 7.955311 10.333236 0 0 0</div><div class="">W 6.645429 7.955311 10.333236 0 0 0</div><div class="">W 10.809008 7.955311 10.333236 0 0 0</div><div class="">W 2.481849 -1.031577 10.333236 0 0 0</div><div class="">W 6.645429 -1.031577 10.333236 0 0 0</div><div class="">W 10.809008 -1.031577 10.333236 0 0 0</div><div class="">N 0.400059 3.944664 10.052766 0 0 0</div><div class="">N 4.563639 3.944664 10.052766 0 0 0</div><div class="">N 8.727218 3.944664 10.052766 0 0 0</div><div class="">N 0.400059 8.438108 10.052766 0 0 0</div><div class="">N 4.563639 8.438108 10.052766 0 0 0</div><div class="">N 8.727218 8.438108 10.052766 0 0 0</div><div class="">N 0.400059 -0.548780 10.052766 0 0 0</div><div class="">N 4.563639 -0.548780 10.052766 0 0 0</div><div class="">N 8.727218 -0.548780 10.052766 0 0 0</div><div class="">W 0.400059 1.617195 10.000000 0 0 0</div><div class="">W 4.563639 1.617195 10.000000 0 0 0</div><div class="">W 8.727218 1.617195 10.000000 0 0 0</div><div class="">W 0.400059 6.110639 10.000000 0 0 0</div><div class="">W 4.563639 6.110639 10.000000 0 0 0</div><div class="">W 8.727218 6.110639 10.000000 0 0 0</div><div class="">W 0.400059 10.604083 10.000000 0 0 0</div><div class="">W 4.563639 10.604083 10.000000 0 0 0</div><div class="">W 8.727218 10.604083 10.000000 0 0 0</div><div class="">C 10.809008 2.628097 19.750000</div><div class="">H 10.177000 1.997000 20.383000</div><div class="">H 11.443000 1.997000 19.117000</div><div class="">H 10.177000 3.263000 19.117000</div><div class="">H 11.443000 3.263000 20.383000</div><div class=""><br class=""></div><div class="gmail-yj6qo"></div></div></div></div>
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