[DFTB-Plus-User] Problem of periodic structure optimization

[冯帅]

Dear all:
   I want to optimize a structure of two molecules absorbed on a periodic TiO2 surface. But the structure of the periodic system cannot converge after several steps. I changed my initial  configuration several times, but the problem has not gone away. So I attach my input files to seek help that whether the parameters are wrong.


Geometry = GenFormat {
 <<< "geom-start.gen"
}


Driver = ConjugateGradient {
 LatticeOpt = Yes
 MovedAtoms = {}
 MaxForceComponent = 5.000000000000000E-004  # Identical to Fan
  MaxSteps = 99999
  OutputPrefix = "geom.out"
}


Hamiltonian = DFTB {
  SCC = Yes
  SCCTolerance = 1.0E-005  # Identical to Fan
  MaxSCCIterations = 10000
  Mixer = Broyden {}
  Eigensolver = Standard {}                             
  Dispersion = LennardJones {  
  Parameters = UFFParameters {}
 }
  MaxAngularMomentum = {
    Ti = "d"
    O = "p" 
    H = "s" 
    N = "p" 
    C = "p" 
    S = "d" 
  }
  Filling = Fermi {
    Temperature [Kelvin] = 0.0
    }
  Charge = 0.000000000000000E+000
  SpinPolarisation = {}
  SlaterKosterFiles =  {
    Ti-Ti = "/home/zhaoxiuming/fs/sk/tiorg-0-1/Ti-Ti.skf" 
    Ti-O = "/home/zhaoxiuming/fs/sk/tiorg-0-1/Ti-O.skf"   
    Ti-H = "/home/zhaoxiuming/fs/sk/tiorg-0-1/Ti-H.skf"   
    Ti-N = "/home/zhaoxiuming/fs/sk/tiorg-0-1/Ti-N.skf"   
    Ti-C = "/home/zhaoxiuming/fs/sk/tiorg-0-1/Ti-C.skf"   
    Ti-S = "/home/zhaoxiuming/fs/sk/tiorg-0-1/Ti-S.skf"   
    O-Ti = "/home/zhaoxiuming/fs/sk/tiorg-0-1/O-Ti.skf"   
    O-O = "/home/zhaoxiuming/fs/sk/mio-1-1/O-O.skf"       
    O-H = "/home/zhaoxiuming/fs/sk/mio-1-1/O-H.skf"       
    O-N = "/home/zhaoxiuming/fs/sk/mio-1-1/O-N.skf"       
    O-C = "/home/zhaoxiuming/fs/sk/mio-1-1/O-C.skf"       
    O-S = "/home/zhaoxiuming/fs/sk/mio-1-1/O-S.skf"       
    H-Ti = "/home/zhaoxiuming/fs/sk/tiorg-0-1/Ti-H.skf"   
    H-O = "/home/zhaoxiuming/fs/sk/mio-1-1/H-O.skf"       
    H-H = "/home/zhaoxiuming/fs/sk/mio-1-1/H-H.skf"       
    H-N = "/home/zhaoxiuming/fs/sk/mio-1-1/N-H.skf"       
    H-C = "/home/zhaoxiuming/fs/sk/mio-1-1/C-H.skf"       
    H-S = "/home/zhaoxiuming/fs/sk/mio-1-1/H-S.skf"       
    N-Ti = "/home/zhaoxiuming/fs/sk/tiorg-0-1/N-Ti.skf"   
    N-O = "/home/zhaoxiuming/fs/sk/mio-1-1/N-O.skf"       
    N-H = "/home/zhaoxiuming/fs/sk/mio-1-1/N-H.skf"       
    N-N = "/home/zhaoxiuming/fs/sk/mio-1-1/N-N.skf"       
    N-C = "/home/zhaoxiuming/fs/sk/mio-1-1/N-C.skf"       
    N-S = "/home/zhaoxiuming/fs/sk/mio-1-1/N-S-new.skf"   
    C-Ti = "/home/zhaoxiuming/fs/sk/tiorg-0-1/C-Ti.skf"   
    C-O = "/home/zhaoxiuming/fs/sk/mio-1-1/C-O.skf"       
    C-H = "/home/zhaoxiuming/fs/sk/mio-1-1/C-H.skf"       
    C-N = "/home/zhaoxiuming/fs/sk/mio-1-1/C-N.skf"       
    C-C = "/home/zhaoxiuming/fs/sk/mio-1-1/C-C.skf"       
    C-S = "/home/zhaoxiuming/fs/sk/mio-1-1/C-S.skf"       
    S-Ti = "/home/zhaoxiuming/fs/sk/tiorg-0-1/S-Ti.skf"   
    S-O = "/home/zhaoxiuming/fs/sk/mio-1-1/S-O.skf"       
    S-H = "/home/zhaoxiuming/fs/sk/mio-1-1/S-H.skf"       
    S-N = "/home/zhaoxiuming/fs/sk/mio-1-1/S-N-new.skf"   
    S-C = "/home/zhaoxiuming/fs/sk/mio-1-1/S-C.skf"       
    S-S = "/home/zhaoxiuming/fs/sk/mio-1-1/S-S.skf"       
  } 
  KPointsAndWeights = SupercellFolding {
   2  0  0
   0  2  0
   0  0  1
   0.5 0.5 0.0
  } 
}   
    
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