Hi all,
I am trying to do cell optimization of a goethite FeOOH unit cell. The
lattice parameters of the considered unit cell are a=9.91340 b=3.0128,
c=4.58 ( the same values I used in cp2k).
I have tested all three cases (direct cell opt, geo opt, MD) of the
CELL_OPT and
The cell optimized values are approximately a=9.33, b=3.063 c=4.179.
*The experiment values of lattice constants are a=9.96 b=3.02 c=4.62. *
*I want to obtain the optimized values close to expt. values. *
In trail and error, I have used STESS_TENSOR NUMERICAL, I have disabled D3
correction and I have also used zero pressure.
Below is my input file.
&Global
PROJECT goethite_cellopt
RUN_TYPE CELL_OPT
PRINT_LEVEL LOW
&END GLOBAL
&FORCE_EVAL
METHOD Quickstep
STRESS_TENSOR ANALYTICAL
&DFT
BASIS_SET_FILE_NAME BASIS_MOLOPT
POTENTIAL_FILE_NAME GTH_POTENTIALS
CHARGE 0
MULTIPLICITY 1
&MGRID
NGRIDS 5
CUTOFF 600
REL_CUTOFF 60
&END
&QS
METHOD GPW
EPS_DEFAULT 1.0E-12
EXTRAPOLATION ASPC
EXTRAPOLATION_ORDER 4
&END
&SCF
SCF_GUESS ATOMIC
MAX_SCF 1500
EPS_SCF 1.0E-8
&OUTER_SCF
MAX_SCF 30
EPS_SCF 1.0E-8
&END
ADDED_MOS 30
CHOLESKY INVERSE
&SMEAR ON
METHOD FERMI_DIRAC
ELECTRONIC_TEMPERATURE [K] 300
&END SMEAR
&DIAGONALIZATION
ALGORITHM STANDARD
&END DIAGONALIZATION
&MIXING
METHOD BROYDEN_MIXING
ALPHA 0.1
BETA 1.5
NBROYDEN 8
&END MIXING
&END SCF
&XC
&XC_FUNCTIONAL PBE
&END XC_FUNCTIONAL
&VDW_POTENTIAL
POTENTIAL_TYPE PAIR_POTENTIAL
&PAIR_POTENTIAL
PARAMETER_FILE_NAME dftd3.dat
TYPE DFTD3
REFERENCE_FUNCTIONAL PBE
R_CUTOFF [angstrom] 15
&END
&END VDW_POTENTIAL
&END XC
&END DFT
&SUBSYS
&CELL
ABC [angstrom] 9.91340 3.01280 4.58000
PERIODIC XYZ
&END CELL
&TOPOLOGY
COORD_FILE_NAME goethite_unitcell.xyz
COORD_FILE_FORMAT XYZ
&CENTER_COORDINATES T
&END CENTER_COORDINATES
&END
&KIND H
BASIS_SET DZVP-MOLOPT-SR-GTH
POTENTIAL GTH-PBE-q1
&END KIND
&KIND Fe
BASIS_SET DZVP-MOLOPT-SR-GTH
POTENTIAL GTH-PBE-q16
&END KIND
&KIND O
BASIS_SET DZVP-MOLOPT-SR-GTH
POTENTIAL GTH-PBE-q6
&END KIND
&END SUBSYS
&END FORCE_EVAL
&MOTION
&CELL_OPT
OPTIMIZER BFGS
MAX_ITER 5000
KEEP_ANGLES T
EXTERNAL_PRESSURE 1.01325 0 0 0 1.01325 0 0 0 1.01325
&END
&END
Goethite unit cell
16
Fe H O2
Fe 1.446365 0.753200 4.357412
Fe 8.467034 2.259600 0.222588
Fe 3.510335 2.259600 2.067412
Fe 6.403065 0.753200 2.512588
H 8.912147 0.753200 2.752580
H 1.001253 2.259600 1.827420
H 5.957953 2.259600 0.462580
H 3.955446 0.753200 4.117420
O 7.940633 0.753200 1.305300
O 1.972767 2.259600 3.274700
O 6.929466 2.259600 3.595300
O 2.983933 0.753200 0.984700
O 9.400877 0.753200 3.682320
O 0.512523 2.259600 0.897680
O 5.469223 2.259600 1.392320
O 4.444177 0.753200 3.187680
Please let me know if you have any suggestions.
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