Hello, <br>I'm trying to do an energy minimization of slab-like planar
structure and I cannot get convergence of steepest descents or cg
method. In a separate, but possibly related issue, I can't get the scc
calculation to converge either. I started with a 1x1 unit cell "slab"
of the material, then a 2x2 unit cell slab. These both converge in
around 8 iterations. If I scale up to 3x3 cells or greater, I do not
achieve convergence and the energy oscilates or actually goes up. Any
suggestions for achieving convergence for energy minimization and / or
scc? Ideally I'd like to scale up to a 10x5 unit cell slab for my
calculations. <br>
<br>Attached are the input files for a 2x2 and 3x3 unit cell energy minimization calculations with scc off.<br><br>Thanks in advance for your assistance!<br><br>Dave Schall<br><br>#2x2 unit cell: Converges just fine.<br>
Geometry = GenFormat {<br>
32 S<br>C H<br>1 1 -2.5319 -0.2582 -4.3855<br>2 1 -1.2659 0.2584 -3.6545<br>3 1 -1.2659 -0.2582 -2.1927<br>4 1 -2.5319 0.2584 -1.4617<br>5 2 -2.5319 -1.3798 -4.3855<br>6 2 -1.2659 1.3800 -3.6545<br>7 2 -1.2659 -1.3798 -2.1927<br>
8 2 -2.5319 1.3800 -1.4617<br>9 1 0.0001 -0.2582 -4.3855<br>10 1 1.2661 0.2584 -3.6545<br>11 1 1.2661 -0.2582 -2.1927<br>12 1 0.0001 0.2584 -1.4617<br>13 2 0.0001 -1.3798 -4.3855<br>14 2 1.2661 1.3800 -3.6545<br>15 2 1.2661 -1.3798 -2.1927<br>
16 2 0.0001 1.3800 -1.4617<br>17 1 -2.5319 -0.2582 0.0001<br>18 1 -1.2659 0.2584 0.7310<br>19 1 -1.2659 -0.2582 2.1929<br>20 1 -2.5319 0.2584 2.9238<br>21 2 -2.5319 -1.3798 0.0001<br>22 2 -1.2659 1.3800 0.7310<br>23 2 -1.2659 -1.3798 2.1929<br>
24 2 -2.5319 1.3800 2.9238<br>25 1 0.0001 -0.2582 0.0001<br>26 1 1.2661 0.2584 0.7310<br>27 1 1.2661 -0.2582 2.1929<br>28 1 0.0001 0.2584 2.9238<br>29 2 0.0001 -1.3798 0.0001<br>30 2 1.2661 1.3800 0.7310<br>31 2 1.2661 -1.3798 2.1929<br>
32 2 0.0001 1.3800 2.9238<br>0.0 0.0 0.0<br>5.0640000000000001 0.0 0.0<br>0.0 20.000000000000000 0.0<br>0.0 0.0 8.7711518399999999<br>}<br>Driver = ConjugateGradient {<br> MovedAtoms = Range { 1 -1 }<br> MaxForceComponent [eV/AA] = 1.0e-2<br>
MaxSteps = 100<br># StepSize = 0.1<br> OutputPrefix = "geo_end"<br>}<br>Hamiltonian = DFTB {<br> SCC = No<br> MaxAngularMomentum = {<br> C = "p"<br> H = "s"<br># Eigensolver = Standard{}<br>
}<br> SlaterKosterFiles = Type2FileNames {<br> Prefix = "/home/schall2/Research/<div id=":8i" class="ii gt">splines/slako/pbc-0-2/"<br> Separator = "-"<br> Suffix = ".skf"<br> }<br>
KPointsAndWeights = SupercellFolding {<br>
2 0 0<br> 0 2 0<br> 0 0 2 <br> 0.5 0.5 0.5<br> }<br> Eigensolver = Standard{}<br>}<br><br>#3x3 unit cell: Does not converge!<br>Geometry = GenFormat {<br> 72 S<br>C H <br>1 1 -3.7979 -0.2582 -6.5783<br>
2 1 -2.5319 0.2584 -5.8473<br>3 1 -2.5319 -0.2582 -4.3855<br>4 1 -3.7979 0.2584 -3.6545<br>5 2 -3.7979 -1.3798 -6.5783<br>6 2 -2.5319 1.3800 -5.8473<br>7 2 -2.5319 -1.3798 -4.3855<br>8 2 -3.7979 1.3800 -3.6545<br>9 1 -1.2659 -0.2582 -6.5783<br>
10 1 0.0001 0.2584 -5.8473<br>11 1 0.0001 -0.2582 -4.3855<br>12 1 -1.2659 0.2584 -3.6545<br>13 2 -1.2659 -1.3798 -6.5783<br>14 2 0.0001 1.3800 -5.8473<br>15 2 0.0001 -1.3798 -4.3855<br>16 2 -1.2659 1.3800 -3.6545<br>17 1 1.2661 -0.2582 -6.5783<br>
18 1 2.5321 0.2584 -5.8473<br>19 1 2.5321 -0.2582 -4.3855<br>20 1 1.2661 0.2584 -3.6545<br>21 2 1.2661 -1.3798 -6.5783<br>22 2 2.5321 1.3800 -5.8473<br>23 2 2.5321 -1.3798 -4.3855<br>24 2 1.2661 1.3800 -3.6545<br>25 1 -3.7979 -0.2582 -2.1927<br>
26 1 -2.5319 0.2584 -1.4617<br>27 1 -2.5319 -0.2582 0.0001<br>28 1 -3.7979 0.2584 0.7310<br>29 2 -3.7979 -1.3798 -2.1927<br>30 2 -2.5319 1.3800 -1.4617<br>31 2 -2.5319 -1.3798 0.0001<br>32 2 -3.7979 1.3800 0.7310<br>33 1 -1.2659 -0.2582 -2.1927<br>
34 1 0.0001 0.2584 -1.4617<br>35 1 0.0001 -0.2582 0.0001<br>36 1 -1.2659 0.2584 0.7310<br>37 2 -1.2659 -1.3798 -2.1927<br>38 2 0.0001 1.3800 -1.4617<br>39 2 0.0001 -1.3798 0.0001<br>40 2 -1.2659 1.3800 0.7310<br>41 1 1.2661 -0.2582 -2.1927<br>
42 1 2.5321 0.2584 -1.4617<br>43 1 2.5321 -0.2582 0.0001<br>44 1 1.2661 0.2584 0.7310<br>45 2 1.2661 -1.3798 -2.1927<br>46 2 2.5321 1.3800 -1.4617<br>47 2 2.5321 -1.3798 0.0001<br>48 2 1.2661 1.3800 0.7310<br>49 1 -3.7979 -0.2582 2.1929<br>
50 1 -2.5319 0.2584 2.9238<br>51 1 -2.5319 -0.2582 4.3857<br>52 1 -3.7979 0.2584 5.1166<br>53 2 -3.7979 -1.3798 2.1929<br>54 2 -2.5319 1.3800 2.9238<br>55 2 -2.5319 -1.3798 4.3857<br>56 2 -3.7979 1.3800 5.1166<br>57 1 -1.2659 -0.2582 2.1929<br>
58 1 0.0001 0.2584 2.9238<br>59 1 0.0001 -0.2582 4.3857<br>60 1 -1.2659 0.2584 5.1166<br>61 2 -1.2659 -1.3798 2.1929<br>62 2 0.0001 1.3800 2.9238<br>63 2 0.0001 -1.3798 4.3857<br>64 2 -1.2659 1.3800 5.1166<br>65 1 1.2661 -0.2582 2.1929<br>
66 1 2.5321 0.2584 2.9238<br>67 1 2.5321 -0.2582 4.3857<br>68 1 1.2661 0.2584 5.1166<br>69 2 1.2661 -1.3798 2.1929<br>70 2 2.5321 1.3800 2.9238<br>71 2 2.5321 -1.3798 4.3857<br>72 2 1.2661 1.3800 5.1166<br>0.0 0.0 0.0<br>
7.5960000000000001 0.0 0.0<br>0.0 20.000000000000000 0.0<br>0.0 0.0 13.156727759999999<br>}<br>Driver = ConjugateGradient {<br> MovedAtoms = Range { 1 -1 }<br> MaxForceComponent [eV/AA] = 1.0e-2<br> MaxSteps = 100<br>
# StepSize = 0.1<br> OutputPrefix = "geo_end"<br>}<br>Hamiltonian = DFTB {<br> SCC = No<br> MaxAngularMomentum = {<br> C = "p"<br> H = "s"<br># Eigensolver = Standard{}<br> }<br>
SlaterKosterFiles = Type2FileNames {<br> Prefix = "/home/schall2/Research/splines/slako/pbc-0-2/"<br> Separator = "-"<br> Suffix = ".skf"<br> }<br> KPointsAndWeights = SupercellFolding {<br>
2 0 0<br> 0 2 0<br> 0 0 2 <br> 0.5 0.5 0.5<br> }<br> Eigensolver = Standard{}<br>}</div><br clear="all"><br>-- <br>J. David Schall, Assistant Professor<br>Dept. of Mechanical Engineering, Oakland University<br>
130 DHE, Rochester, MI 48309<br>248-370-2870<br>