[DFTB-Plus-User] problems with charged systems

[Christian Pomelli]

I start few days ago to use dftb+.
My main research interest is in ionic liquids thus I start to
calculate the geometry of some ions.
In the case of two common cations the code stop for an error in
diagonalized (Failure in diagonalisation routine dsygvd)
The tentatives of change the diagonalizer  do not change nothing. I
start from PM6 optimized geometries

These are the two input files:

DABCO ion

Geometry = GenFormat {
24  C
 N C H
 1   2           -2.5030875489  -0.3940165844   0.1866180646
 2   2           -3.0636894900   1.0546918947   0.1869669245
 3   3           -2.8687790569  -0.9620673562  -0.699448508
 4   3           -2.8684574270  -0.9623511743   1.0726383367
 5   3           -3.7068279871   1.2301296208  -0.703186179
 6   3           -3.7058266896   1.2300749585   1.0778615334
 7   2           -0.5237384830   0.3215237749  -1.0290678447
 8   3            0.5897821116   0.2881870741  -1.0511207562
 9   3           -0.8534628570  -0.2339009817  -1.9369866852
10   2           -1.0356526996   1.7878328007  -1.0592665481
11   3           -0.1847264516   2.5033541011  -1.0863311935
12   3           -1.6356030144   1.9784905929  -1.9760558044
13   2           -1.0346755300   1.7881510891   1.4314212283
14   3           -0.1834624259   2.5033833588   1.4573311119
15   3           -1.6337141077   1.9795061195   2.3486537764
16   2           -0.5232976998   0.3216493780   1.4015108976
17   3            0.5902174362   0.2879336088   1.4233935616
18   3           -0.8530668908  -0.2334416731   2.3096144711
19   2           -2.4050443492   3.4625532213   0.1864002497
20   3           -1.5778852422   4.1996792899   0.1861191282
21   3           -3.0289678335   3.6751338563  -0.7041479563
22   3           -3.0284934162   3.6752807807   1.0772455113
23   1           -1.0103292987  -0.3956425332   0.1863470181
24   1           -1.8925157663   2.0447471537   0.1863806571
}

Driver = ConjugateGradient {
  MovedAtoms = Range { 1 -1 }
  MaxForceComponent = 1.0e-4
  MaxSteps = 100
  OutputPrefix = "geom.out"
}

Hamiltonian = DFTB {
  SCC = Yes
  SCCTolerance = 1.0e-5
  MaxSCCIterations = 1000
  Mixer = Anderson {
  }
EigenSolver = DivideAndConquer{}
  SlaterKosterFiles = {
    N-N = "N-N.skf"
    C-C = "C-C.skf"
    H-H = "H-H.skf"
    N-H = "N-H.skf"
    N-C = "N-C.skf"
    C-H = "C-H.skf"
    C-N = "C-N.skf"
    H-C = "H-C.skf"
    H-N = "H-N.skf"
  }
  MaxAngularMomentum = {
    H = "p"
    N = "d"
    C = "d"
  }
  Charge = +1.0
  SpinPolarisation = {}
  Filling = Fermi {
    Temperature [Kelvin] = 0.0
  }
}

Options = {}

ParserOptions = {
  ParserVersion = 3
}


------

BMIM ion

Geometry = GenFormat {
25  C
 N C H
 1	2                 -1.96128804    1.91918361   -0.60036999
 2 	2                 -0.88165519    3.47370955   -1.87719396
 3 	2                 -2.22002051    3.86368342   -1.72928380
 4 	1                 -2.87169326    2.91208311   -0.95024731
 5 	3                 -2.25538700    1.06800697    0.01241634
 6 	3                 -0.11316613    4.00414845   -2.42934885
 7 	3                 -2.74370407    4.73634013   -2.11742241
 8 	1                 -0.71770467    2.24090985   -1.16152567
 9 	2                 -4.28879104    2.94922223   -0.56120417
10 	3                 -4.87097645    2.41570921   -1.28323187
11 	3                 -4.40696200    2.49326848    0.39954647
12 	3                 -4.61992717    3.96572228   -0.51674618
13 	2                  0.52289173    1.46176213   -1.04007852
14 	2                  1.04308865    1.08820051   -2.40391356
15 	3                  0.30735659    0.54735606   -0.43598337
16 	3                  1.27301001    2.07718442   -0.48677598
17 	2                  2.32262842    0.28371665   -2.31152369
18 	3                  0.26711168    0.49223506   -2.95336125
19 	3                  1.25094466    2.02055940   -2.99274338
20 	2                  2.84277456   -0.08989062   -3.67538327
21 	3                  3.09859154    0.87966881   -1.76209864
22 	3                  2.13572942   -0.64586273   -1.71143376
23 	3                  3.78527058   -0.68164971   -3.58334351
24 	3                  2.09252609   -0.70520515   -4.22862799
25 	3                  3.05800082    0.82460490   -4.27948595
}

Driver = ConjugateGradient {
  MovedAtoms = Range { 1 -1 }
  MaxForceComponent = 1.0e-4
  MaxSteps = 100
  OutputPrefix = "geom.out"
}

Hamiltonian = DFTB {
  SCC = Yes
  SCCTolerance = 1.0e-5
  MaxSCCIterations = 1000
  Mixer = Anderson {
  }
EigenSolver = Standard{}
  SlaterKosterFiles = {
    N-N = "N-N.skf"
    C-C = "C-C.skf"
    H-H = "H-H.skf"
    N-H = "N-H.skf"
    N-C = "N-C.skf"
    C-H = "C-H.skf"
    C-N = "C-N.skf"
    H-C = "H-C.skf"
    H-N = "H-N.skf"
  }
  MaxAngularMomentum = {
    H = "p"
    N = "d"
    C = "d"
  }
  Charge = +1.0
  SpinPolarisation = {}
  Filling = Fermi {
    Temperature [Kelvin] = 0.0
  }
}

Options = {}

ParserOptions = {
  ParserVersion = 3
}






-- 
.cris
http://www.rtil.it/pmwiki/pmwiki.php/Staff/ChristianSilvioPomelli