Mulliken charge problem

obo bo... at matcalc.de
Mon Aug 3 10:23:15 CEST 2009


Dear cp2k Users,
I've made some calculations with alpha quarz. At first I have
optimized the hexagonal cell with 9 atoms. I've got the initial
coordinates from a cell optimization in another ab initio programm.
The relaxation in cp2k was sucessfull and the mulliken charges from
the Si atoms are approximately the same. Now I have constructed an
orthorhombic cell with 19 atoms. I've constructed the basis from the
coordinates of the relaxed hexagonal cell. The length of the cell
vectors are also calculated from the hexagonal cell vectors(a, 3^0.5,
c).
When I start the cell optimization, I get the following mulliken
charges:
  Atom     |    Charge
     1  Si    1.370421
     2  Si    1.349422
     3  Si    0.726644
     4  O    -0.611734
     5  O    -0.644209
     6  O    -0.595641
     7  O    -0.609976
     8  O    -0.586622
     9  O    -0.647799
    10  Si    1.473611
    11  Si    1.489633
    12  Si    0.829598
    13  O    -0.609031
    14  O    -0.568553
    15  O    -0.591643
    16  O    -0.610546
    17  O    -0.600818
    18  O    -0.562758
  Total       0.000000


At the end of the cell optimization, the relation between the cell
vectors (a and 3^0.5*a) are also wrong.
What is my mistake??? Can somebody help me?

The input file:

&FORCE_EVAL
  METHOD Quickstep
  STRESS_TENSOR NUMERICAL
  &DFT
     &POISSON
       PERIODIC XYZ
       POISSON_SOLVER PERIODIC
       &EWALD
        EWALD_TYPE SPME
       &END
     &END POISSON
    &MGRID
      CUTOFF 650
      RELATIVE_CUTOFF 85.0
    &END MGRID
    &QS
     WF_INTERPOLATION PS
     EXTRAPOLATION_ORDER 4
    &END QS
    &SCF
      EPS_SCF 1.E-6
      CHOLESKY OFF
      MAX_SCF 50
      SCF_GUESS ATOMIC
      &OUTER_SCF
        DIIS_BUFFER_LENGTH 5
	OPTIMIZER DIIS
      &END OUTER_SCF
    &END SCF
    &XC
       &XC_GRID
        XC_DERIV SPLINE3
       &END XC_GRID
       &XC_FUNCTIONAL PBE
       &END XC_FUNCTIONAL
    &END XC
  &END DFT
  &SUBSYS
    &CELL
      PERIODIC XYZ
      MULTIPLE_UNIT_CELL 1 1 1
      ABC 4.805 8.3225 5.393
      ALPHA_BETA_GAMMA  90.0 90.0 90.0
    &END CELL
    &COORD
Si 1.1328078594000004 6.4061604696       3.5954303785000006
Si 1.1329589190000002 1.9039591092000003 1.7978168006000006
Si 2.6289910789000004 8.3163249591       5.3929132817
O 1.6426232969999999  7.8451213509999995 4.154876766399999
O 4.4371215705        1.6255884538000005 2.3576057410000004
O 3.6202186447        7.155568958499999  0.5597043610000001
O 1.6427913173999997  0.4650789015000002 1.237976828999999
O 3.620111714099999   1.1547964305000002 4.8334310334
O 4.4368490245        6.684213627799998  3.035570217399999
Si 3.4358078594       2.2346604696       3.5954303785000006
Si 3.435958918999999  6.054959109200001  1.7978168006000006
Si 0.1269910789       4.144824959099999  5.3929132817
O 3.9456232970000005  3.6736213510000013 4.154876766399999
O 1.9351215704999998  5.776588453800002  2.3576057410000004
O 1.1182186447000002  2.984068958500001  0.5597043610000001
O 3.9457913174000008  4.616078901500002  1.237976828999999
O 1.1181117141        5.305796430500002  4.8334310334
O 1.9348490245        2.5127136278000006 3.035570217399999
     &END COORD
    &KIND Si
      BASIS_SET DZVP-GTH-PBE
      POTENTIAL GTH-PBE-q4
    &END KIND
    &KIND O
      BASIS_SET DZVP-GTH-PBE
      POTENTIAL GTH-PBE-q6
    &END KIND
    &KIND H
      BASIS_SET DZVP-GTH-PBE
      POTENTIAL GTH-PBE-q1
    &END KIND
    &TOPOLOGY
     CENTER_COORDINATES T
     &DUMP_PDB
     &END
       MULTIPLE_UNIT_CELL 1 1 1
    &END TOPOLOGY
  &END SUBSYS
&END FORCE_EVAL
&GLOBAL
  PROJECT SiO-Cell
  RUN_TYPE CELL_OPT
  PRINT_LEVEL MEDIUM
&END GLOBAL
&MOTION
  &GEO_OPT
  MAX_ITER 200
  OPTIMIZER BFGS
  MAX_FORCE 5.0E-5
  &END GEO_OPT
  &CELL_OPT
   EXTERNAL_PRESSURE [bar] 0.0
   PRESSURE_TOLERANCE 15.0
   MAX_ITER 900
   KEEP_ANGLES TRUE
   OPTIMIZER CG
   &CG
    &LINE_SEARCH
      TYPE 2PNT
    &END LINE_SEARCH
   &END CG
  &END CELL_OPT
&END MOTION

thanks
Oliver


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