[DFTB-Plus-User] Bulk/slab Fe optimization problems using pbc-0-3 or trans3d-0-1 parameters

[Bálint Aradi]

Dear Branislav,

could you try to set ShellResolvedScc = Yes for the iron calculation? 
Does this improve reuslts?

Best regards,

Bálint


On 28.01.23 14:18, Branislav Milovanović wrote:
> Dear DFTB+ users,
> 
> I am experiencing problems with bulk Fe (iron) optimization using 
> pbc-0-3 or trans3d-0-1 parameters.
> Namely, I wanted to optimize Fe unit cell first, then supercell, then to 
> construct slab Fe(100) surface and later
> to try and investigate adsorption of different organic molecules on 
> Fe(110) surface (using mio-1-1 + trans3d-0-1 parameters set).
> 
> I've tried all kind of different setup in the DFTB+ input but somehow my 
> system always fell apart during the optimization runs.
> Fe-Fe distances become too large, >3.5 A and experimental values are 
> ~2.86 A. Here is my current input file:
> 
> Geometry = GenFormat {
>    <<< geo.gen
> }
> 
> Driver = GeometryOptimisation {
>    Optimiser = Rational {
>      DiagLimit = 1.00E-002
>    }
>    LatticeOpt = Yes
>    FixAngles = Yes
>    FixLengths = {No No No}
>    Isotropic = Yes
>    MovedAtoms = "1:-1"
>    Convergence = {
>      GradElem = 0.00001
>      DispElem = 0.0001
>    }
>    MaxSteps = 1000
>    OutputPrefix = "geo_end"
>    AppendGeometries = Yes
> }
> 
> Hamiltonian = DFTB {
>    SCC = Yes
>    SCCTolerance = 1.0E-9
>    MaxSCCIterations = 500
>    Charge = 0
>    Solver = RelativelyRobust {}
>    ThirdOrder = No
>    ThirdOrderFull = No
>    Mixer = Broyden {
>      MixingParameter = 0.20000000000000001
>      InverseJacobiWeight = 1.0000000000000000E-002
>      MinimalWeight = 1.0000000000000000
>      MaximalWeight = 100000.00000000000
>      WeightFactor = 1.0000000000000000E-002
>    }
>    Filling = Fermi {
>      Temperature = 1500.000
>    }
>    KPointsAndWeights = SuperCellFolding {
>      8 0 0
>      0 8 0
>      0 0 8
>      0.5 0.5 0.5
>    }
>    ShellResolvedSCC = Yes
> #  ShellResolvedSpin = Yes
>    SpinPolarisation = Colinear {
>      UnpairedElectrons = 4
>      RelaxTotalSpin = Yes
>    }
>    SpinConstants = {
>      Fe = {
>     -0.0160    -0.0124    -0.0035     # pbc
>     -0.0124    -0.0280    -0.0010
>     -0.0035    -0.0010    -0.0155
> #-0.016 -0.012 -0.003             # trans3d
> #-0.012 -0.029 -0.001
> #-0.003 -0.001 -0.018
> }
>    }
>    SlaterKosterFiles = Type2FileNames {
>      Prefix = 
> "/home/branislavm/branislavm/Programs/Potentials/slako/pbc/pbc-0-3/"    
>    # 
> "/home/branislavm/branislavm/Programs/Potentials/slako/mio-1-1+trans3d-0-1/"
>      Separator = "-"
>      Suffix = ".skf"
>      LowerCaseTypeName = No
>    }
>    MaxAngularMomentum = {
>      Fe = "d"
> #    C = "p"
> #    O = "p"
> #    H = "s"
>    }
> #  Dispersion = DftD4 {
> #    s6 = 1.0000000
> #    s8 = 1.1948145
> #    s9 = 0.0000000
> #    a1 = 0.6074567
> #    a2 = 4.9336133
> #    s10 = 0.000000
> #    alpha = 16.000
> #  }
>    PolynomialRepulsive = {}
>    OldSKInterpolation = No
>    RangeSeparated = None {}
>    ReadInitialCharges = No
>    InitialCharges = {}
>    ConvergentSCCOnly = Yes
>    HCorrection = None {}
>    ElectricField = {}
>    OnSiteCorrection = {}
>    Solvation = {}
>    Electrostatics = GammaFunctional {}
>    ForceEvaluation = "Traditional"
> }
> 
> ParserOptions = {
>    ParserVersion = 12
>    WriteHSDInput = Yes
>    StopAfterParsing = No
>    IgnoreUnprocessedNodes = No
> }
> 
> Reks = None {}
> 
> Analysis = {
>    ProjectStates = {}
>    WriteEigenvectors = No
>    WriteBandOut = No
>    MullikenAnalysis = No
>    AtomResolvedEnergies = No
>    CalculateForces = No
> }
> 
> ExcitedState = {}
> 
> Options = {
>    WriteDetailedOut = Yes
>    WriteAutotestTag = No
>    WriteDetailedXML = No
>    WriteResultsTag = No
>    RandomSeed = 0
>    WriteHS = No
>    WriteRealHS = No
>    MinimiseMemoryUsage = No
>    ShowFoldedCoords = No
>    TimingVerbosity = 1
>    WriteChargesAsText = Yes
> }
> 
> 
> I would appreciate if someone could point me out where I'm making mistakes.
> Thanks in advance!
> 
> Kind regards,
> Branislav
> 
> 
> _______________________________________________
> DFTB-Plus-User mailing list
> DFTB-Plus-User at mailman.zfn.uni-bremen.de
> https://mailman.zfn.uni-bremen.de/cgi-bin/mailman/listinfo/dftb-plus-user

-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b-aradi/


-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature
Type: application/pgp-signature
Size: 840 bytes
Desc: OpenPGP digital signature
URL: <http://mailman.zfn.uni-bremen.de/pipermail/dftb-plus-user/attachments/20230130/38a87e1b/attachment.sig>