[DFTB-Plus-User] problem: CO2 on a cluster was bended

Ol Ga o.gaeurisco at gmail.com
Wed Nov 21 22:36:36 CET 2012


Dear DFTB+ Users and Developers,

I would kindly ask you to clarify for me a situation. I optimized big
enough water ice cluster (270*H2O) with 12CO2 molecules. I used an
input card introduced below.
However, after convergence of the full geometry optimization I
observed that CO2 molecules are not linear, i.e. they were bended up
to 175 degrees. Certainly, the adsorption energy is unphysical high.
I would kindly ask you to inspect the input whether it may contain any
logical error (I am new in dftb+, thus I am a bit worried that I can
miss something).
I would kindly ask you to provide your opinion.

Thank you in advance.


Sincerely,
Oleg B. Gadzhiev, PhD


My input (the coordinates were cut out):

Geometry = GenFormat {
845  C
H  O  C
1 2    0.6673144000E+01   -0.6246893000E+01    0.3770555000E+01
2 2    0.7013002000E+01   -0.8860777000E+01    0.3003913000E+01
3 2    0.7090858000E+01   -0.9369160000E+01    0.5761455000E+01
4 2    0.6786158000E+01   -0.6651540000E+01    0.6484645000E+01
5 2    0.9245803000E+01   -0.5425467000E+01    0.6360986000E+01
6 2    0.9414741000E+01   -0.5107457000E+01   -0.3678316000E+01

[a lots of atoms]


842 2    0.1069978549E-01   -0.1240239426E+02    0.1424776465E+01
843 3   -0.1018751177E+02   -0.7452181350E+01   -0.1172457669E+01
844 2   -0.1056348166E+02   -0.6724966728E+01   -0.2002820449E+01
845 2   -0.9825407954E+01   -0.8238412304E+01   -0.3891588062E+00
}
Driver = ConjugateGradient {
  MovedAtoms = 1:-1
  MaxForceComponent = 1.000000000000000E-005
  MaxSteps = 3000
  AppendGeometries = No
  OutputPrefix = "geom.out"
  LatticeOpt = No
  ConvergentForcesOnly = Yes
  Constraints = {}
}
Hamiltonian = DFTB {
  SCC = Yes
  SCCTolerance = 1.0E-05
  MaxSCCIterations = 1000
  Mixer = Anderson {
    MixingParameter = 5.000000000000000E-002
    Generations = 8
    InitMixingParameter = 1.000000000000000E-002
    DynMixingParameters = {}
    DiagonalRescaling = 1.000000000000000E-002
  }
  MaxAngularMomentum = {
    O = "p"
    C = "p"
    H = "s"
  }
  Charge = 0.000000000000000E+000
  SpinPolarisation = {}
  Eigensolver = Standard {}
  Filling = Fermi {
    Temperature [Kelvin] = 0.000000
  }
  SlaterKosterFiles = {
    O-H = "/home/work/dftb+/mio-1-1/O-H.skf"
    H-O = "/home/work/dftb+/mio-1-1/H-O.skf"
    H-H = "/home/work/dftb+/mio-1-1/H-H.skf"
    O-O = "/home/work/dftb+/mio-1-1/O-O.skf"
    O-C = "/home/work/dftb+/mio-1-1/O-C.skf"
    C-O = "/home/work/dftb+/mio-1-1/C-O.skf"
    C-C = "/home/work/dftb+/mio-1-1/C-C.skf"
    C-H = "/home/work/dftb+/mio-1-1/C-H.skf"
    H-C = "/home/work/dftb+/mio-1-1/H-C.skf"
  }
  ReadInitialCharges = No
  PolynomialRepulsive = {}
  OldRepulsiveSum = No
  OrbitalResolvedSCC = No
  OldSKInterpolation = No
  InitialCharges = {}
  ElectricField = {}
  DampXH = No
  Dispersion = {}
  ThirdOrder = No
  ThirdOrderFull = No
}
Options = {
  WriteAutotestTag = Yes
  WriteEigenvectors = No
  WriteDetailedXML = No
  WriteResultsTag = No
  WriteDetailedOut = Yes
  WriteBandOut = Yes
  AtomResolvedEnergies = No
  RandomSeed = 0
  WriteHS = No
  WriteRealHS = No
  MinimiseMemoryUsage = No
  ShowFoldedCoords = No
}
ParserOptions = {
  ParserVersion = 4
  WriteHSDInput = Yes
  WriteXMLInput = No
  StopAfterParsing = No
  IgnoreUnprocessedNodes = No
}
Analysis = {
  ProjectStates = {}
}


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