[DFTB-Plus-User] DFTB-MD with surfaces and amorphous materials

Vanessa Gruner vgruner08 at gmail.com
Thu Jun 20 19:03:40 CEST 2013


Dear DFTB+ Community,

I have a couple of very general newbie questions:

(1) Can DFTB+ be used to perform MD simulations with surfaces? I gather
from one of the example MD simulations, 'SiH-surface', that comes with the
latest version (v 1.2.2) that DFTB+ is capable of performing simulations
with surfaces. However, when I tried a simple test, in which I took the
input from a well-behaved DFTB-MD simulation and increased the lattice
vector along the z-axis (to reflect a surface), I found that the first time
step of the simulation doesn't converge. (See input below. I'm using
version 1.2.2.) Am I correct about my assumption that DFTB+ can perform
DFTB-MD simulations with surfaces? If so, what might I be doing incorrectly?

(2) My other somewhat related question is about whether or not DFTB+ is
appropriate to perform DFTB-MD simulations with amorphous systems. I assume
that this is true if the system is treated as a non-periodic (or "cluster")
system, but is it possible to treat them as a periodic system?

Thanks in advance,
Vanessa

*****************************************
Geometry = GenFormat {
    72  S
 Si  O
    1  1    2.72029188          0.02565985          3.56986498
    2  1   -1.37222083          2.37392581          7.18904764
    3  1    3.55772121          6.24406872          5.34132995
    4  1    2.73015909          0.02472705          9.02003048
    5  1    3.50916011          6.19491278          0.05278952
    6  1   -1.36587576          2.33303499          1.82845551
    7  1    0.21392498          4.22011286          3.61758699
    8  1    1.15483394          6.52817653          7.15472754
    9  1   -1.36623812          6.16013967          5.41390632
   10  1    3.54494407          2.34389853          7.24386288
   11  1    5.12837336          4.32361900          8.99186871
   12  1    5.98616310          1.91961151          0.03495400
   13  1    0.21520582          4.25139273          9.03527082
   14  1    1.06553066          6.50331471          1.80351714
   15  1   -1.39473082          6.17984802          0.01011540
   16  1    3.53020826          2.29806647          1.78274061
   17  1    5.15076019          4.23935875          3.55101978
   18  1    6.09586279          1.94097506          5.39601692
   19  1    7.59562220         -0.01773099          3.63060204
   20  1   -3.82008684          6.61140748          7.18137783
   21  1    1.16335163          1.92884348          5.26701562
   22  1    7.62369313          0.01700696          8.99464123
   23  1    1.06938209          1.94121886          0.05176643
   24  1   -3.82202230          6.58354265          1.85185380
   25  2    1.40523314          2.95988133          3.91037753
   26  2    1.72708303          8.16566341          7.56525561
   27  2   -3.09201949          5.85154799          5.73260807
   28  2    1.88040125          2.51381062          6.77289690
   29  2    6.20118782          5.70060814          8.67816575
   30  2    6.67777601          0.31785142         10.47693632
   31  2    1.37849458          3.01733602          9.52912724
   32  2    1.71745110          8.15969498          2.22027835
   33  2   -3.02369228          5.89872596          0.47635861
   34  2    1.87931034          2.73459028          1.42254714
   35  2    6.33071833          5.48571989          3.15008045
   36  2    6.62798744          0.27547538          5.06637954
   37  2   -1.15745896          7.15714647          3.96139812
   38  2   -0.72352703          3.96347390          7.59500119
   39  2    1.86999733          5.86446794          5.70552614
   40  2    6.74210430          2.63808881          6.88031381
   41  2    3.81759200          1.32336620          8.60788019
   42  2    4.24131553          4.64083334         10.49970063
   43  2   -1.08919738          7.18892320          9.40124848
   44  2   -0.75250995          3.96097559          2.18066948
   45  2    1.83532070          5.79569727          0.42871622
   46  2    6.73504120          2.64448581          1.45530780
   47  2    3.84161978          1.31181380          3.21820223
   48  2    4.12056514          4.61741162          4.92551810
   49  2    6.26774240          2.89059882          3.93983572
   50  2    4.15063155          3.96650498          7.60839534
   51  2    4.40995040          1.78801055          5.83118613
   52  2   -0.57727847          6.86055182          6.82264507
   53  2    1.39430503          5.52661016          8.59877109
   54  2   -0.74451401          4.58449606         10.45304285
   55  2    6.23477664          2.94319410          9.42351343
   56  2    4.12147464          3.94439978          2.16924673
   57  2    4.26871693          1.58645338          0.35604353
   58  2   -0.61279677          6.81115334          1.44357649
   59  2    1.32523790          5.52790682          3.22924026
   60  2   -0.63346226          4.55474534          5.11798764
   61  2    3.80091615          7.19353005          3.90780547
   62  2   -3.20794979          8.21850114          7.58724208
   63  2   -0.48512069          1.58266627          5.85414470
   64  2    4.29795902          6.89007052          6.79014187
   65  2    8.75619117          1.33174219          8.55370307
   66  2    1.67319916          0.36795164         10.37735539
   67  2    3.75094225          7.17047171          9.40095731
   68  2   -3.19744949          8.18000919          2.19540628
   69  2   -0.59341297          1.59403384          0.43541051
   70  2    4.35867928          6.93475162          1.39258447
   71  2    8.68551580          1.38259432          3.28564629
   72  2    1.77900077          0.29799634          4.98907353
    0.0000000000E+00    0.0000000000E+00    0.0000000000E+00
    0.9831999779E+01    0.0000000000E+00    0.0000000000E+00
   -0.4915999889E+01    0.8514761578E+01    0.0000000000E+00
    0.0000000000E+00    0.0000000000E+00    0.3081079960E+02
}

Driver = VelocityVerlet {
     MovedAtoms    = 1:-1
     Velocities [AA/ps] = {
         1.22753846     -1.44549148      0.52007986
        -1.16193226      1.71592427     -2.96611350
        -0.51667226      1.31320209     -2.78464533
         0.82387823      0.33802238     -2.21187591
        -2.51680060      0.66617915     -0.61438977
        -3.45626295      2.28719719      0.29441515
         1.07307343     -0.07288983     -2.30689875
         2.22366769     -1.97910220     -1.05908445
        -0.95882292     -1.52778550      0.32084103
        -1.77628300      1.58857242      3.24715008
         0.88382664      1.47243976      4.68113718
        -2.07937571     -1.23264950      0.57036683
         4.14406529      0.15671592      1.50681738
         0.44051811     -2.25148849      3.86903633
         1.54368782      1.26653496     -2.42653728
        -1.07582066      2.32594260     -2.12237650
        -0.39890523     -0.83498218     -2.74967070
         2.39615353     -0.48038060      2.82249789
         1.72259485      0.73730937      2.04515594
        -1.59796575      3.78745593     -2.25883529
         1.51940242     -1.41547387     -1.29902560
         0.98467632      1.07344599     -0.07328004
        -0.73787674      0.80889372      6.39192641
        -3.51863797     -3.26170432      2.04789623
         4.09303429      0.45320776     -5.37189146
         0.86974831     -1.55123708     -0.49924088
         0.22152156     -0.81668737      0.43382563
         0.00763047     -3.05030672     -2.33657206
        -2.42572519      3.16593102      1.99941078
         3.71843851      0.97053809     -0.87313943
         0.72487903     12.03699397     -2.37832765
        -4.82622604     -6.00211298     -3.72686610
        -3.39989204     -3.41048293      0.13057839
        -1.79667030      0.80258189     -2.40023694
         3.59186973     -5.16805783     -1.99675412
        -0.44235455      1.97935774      2.08463153
        -0.72773016     -2.62383138      0.17179600
         0.40127289      3.36656663     -0.40458922
        -0.83668930     -0.33097833     -2.09003112
         2.62994405     -0.49309820     -1.63218759
         3.60643570      1.23299920     -0.11822295
         6.51102023     -0.52328831     -2.08384835
        -1.09047170     -2.03615938      6.24703162
        -0.71906732     -1.50425636      1.41861427
        -1.26788200     -4.81906584      0.49266156
         2.03538659      0.34059597      2.72112477
         2.06492685     -0.97953432     -0.89816048
        -0.35600170      0.19177333     -5.15641654
         0.98213957     -0.45888567     -2.76585232
        -3.09374997      3.53340146     -1.00631856
         3.72491724      2.46156787     -5.95468074
        -1.29928529     -2.42910114     -3.08752557
        -0.62200328     -4.94293908     -3.00594796
        -1.95500872      0.15902263      2.06576833
        -3.39441759      5.12135052      0.45093699
        -1.04421151     -3.34798669      0.93375210
        -3.65841706     -2.13278069      1.40192497
        -4.15365092     -0.65839278      1.48891675
        -1.80647764     -0.94435141     -2.38003704
         1.20714017      1.22122294      7.55162096
         1.89954630      0.71674953     -3.15041137
         1.29633496     -1.58329089      1.53311070
         1.16545631     -1.60534347      1.92635599
         0.08063520      0.23817491     -1.91089349
         0.63677512     -3.99598599      1.49466883
        -1.42568040     -2.02168443      0.22120892
        -2.82862914     -1.57720374      2.92832762
         3.25406746      9.38256937      2.28477207
        -4.05067766     -2.44675467      4.28279371
         2.37947502      5.61599558      3.02005787
        -2.75312466     -0.01223718      4.31250136
         4.29640214     -0.35891559     -5.91956245
     }
     Steps = 2000
     TimeStep [fs] = 0.1
     Thermostat = None {}
     MDRestartFrequency = 100
     OutputPrefix       = "quartz_md"
}

Hamiltonian = DFTB {
  SCC = Yes
  SCCTolerance = 1e-5
  OrbitalResolvedSCC = No
  OldSKInterpolation = No
  MaxSCCIterations = 10000
  Mixer = Broyden {
    MixingParameter = 0.200000000000000
    CachedIterations = -1
    InverseJacobiWeight = 1.000000000000000E-002
    MinimalWeight = 1.00000000000000
    MaximalWeight = 100000.000000000
    WeightFactor = 1.000000000000000E-002
  }
  MaxAngularMomentum = {
    Si = d
    O = p
  }
  SlaterKosterFiles {
    Si-Si = "Si-Si.skf"
    Si-O = "Si-O.skf"
    O-Si = "Si-O.skf"
    O-O = "O-O.skf"
  }
  ElectricField = {}
  DampXH = No
  Charge = 0.000000000000000E+000
  ReadInitialCharges = No
  InitialCharges = {
      AllAtomCharges = { # Speci.es net charge for each atom in an H2O
molecule
           1.30958331
           1.31119409
           1.31679545
           1.32863581
           1.33291809
           1.30459996
           1.31828382
           1.30551616
           1.29758822
           1.35624475
           1.30784758
           1.29873300
           1.31695328
           1.31888638
           1.32985898
           1.30287569
           1.31391109
           1.31513485
           1.30830689
           1.30065070
           1.32773165
           1.30290642
           1.32640109
           1.35898748
          -0.63813262
          -0.65882998
          -0.66209268
          -0.66906995
          -0.65133031
          -0.66310043
          -0.65830731
          -0.67956518
          -0.65804428
          -0.65235738
          -0.65132304
          -0.65242555
          -0.66837687
          -0.65721619
          -0.63720581
          -0.64472522
          -0.64505705
          -0.65941631
          -0.66216887
          -0.64769151
          -0.63858459
          -0.64977274
          -0.64962679
          -0.66675013
          -0.65960218
          -0.65731063
          -0.68712602
          -0.65675302
          -0.66156443
          -0.66398658
          -0.67638893
          -0.65178648
          -0.65532433
          -0.65790934
          -0.64984980
          -0.66303605
          -0.64784234
          -0.65446820
          -0.68820843
          -0.65316206
          -0.65413740
          -0.66886040
          -0.65450020
          -0.68146765
          -0.64679716
          -0.66728486
          -0.67983474
          -0.65217272
      }
  }
  SpinConstants = {
   Si = {
     # Wss Wsp Wsd Wps Wpp Wpd Wds Wdp  Wdd
     -0.002 -0.015 0.02 -0.015 -0.014 0.002 0.00 0.00 -0.032
   }
   O = {
     # Wss Wsp Wps Wpp
     -0.035 -0.030 -0.030 -0.028
   }
  }
  SpinPolarisation = Colinear {
    UnpairedElectrons = 0.0
    InitialSpins = {}
   }
  Eigensolver = DivideAndConquer {}
  Filling = Fermi {
    Temperature [Kelvin] = 1.0
  }
  KPointsAndWeights = {
        0.0 0.0 0.0 1.0
  }
  OrbitalPotential = {}
  Dispersion = {}
}

Options {
  WriteAutotestTag = Yes
  WriteEigenvectors = Yes
  WriteDetailedXML = No
  WriteResultsTag = No
  WriteDetailedOut = Yes
  WriteBandOut = Yes
  AtomResolvedEnergies = No
  RandomSeed = 0
  MinimiseMemoryUsage = No
}

ParserOptions {
  ParserVersion = 4
  WriteHSDInput = Yes
  WriteXMLInput = No
  StopAfterParsing = No
  IgnoreUnprocessedNodes = No
}
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