[DFTB-Plus-User] DFTB-problem

[Hakkim Vovusha]

Hi,

  I am doing DFTB calculation for graphene with some hydroxide groups 
(covalently attached). During the optimization hydrogen is flying away 
from the molecule. My input is

Driver = VelocityVerlet {
   Steps = 20000
   TimeStep [Femtosecond] = 2.00000000000000
   Thermostat = Andersen {
     Temperature [Kelvin] = 300.0
#    Temperature [Kelvin] = TemperatureProfile {
#      constant     100    10.0
#      linear       1000  10.0
#      constant    19000  10.0
#      exponential  50     20.0
#    }
     ReselectProbability = 0.200000000000000
     ReselectIndividually = Yes
   }
   OutputPrefix = "geo_end"
   MDRestartFrequency=2
   MovedAtoms = 1:-1
   ConvergentForcesOnly=No
#  Velocities [AA/ps] = {
#<<< "input.vel"
#  }
}

Hamiltonian = DFTB {
#  SCC = Yes
#  SCCTolerance = 1e-5
#  MaxSCCIterations = 1000
   MaxAngularMomentum = {
     C = "p"
     O = "p"
     H = "s"
   }
#  Charge = 0.000000000000000E+000
#  SpinPolarisation = {}
#  Eigensolver = Standard {}
#Mixer = Broyden {
#    MixingParameter = 0.020000000000000
#  }
   Filling = Fermi {
     Temperature [Kelvin] = 300.00
   }
   SlaterKosterFiles = Type2FileNames {
     Prefix = " "
     Separator = "-"
     Suffix = ".skf"
   }
   KPointsAndWeights = SupercellFolding {
    1 0 0
    0 1 0
    0 0 1
    0.0 0.0 0.0
   }
}

Options = {
   WriteAutotestTag = No
   RandomSeed = 12345
}

ParserOptions = {
   ParserVersion = 4
}

Kindly help in this regard

with regards
hakkim