[CP2K:7067] Re: Unusual Behavior of CELL opt progress of CP2K26

[贾建峰]

The lattice parameter of fcc Pt were obtained from reference (https://chemistry.osu.edu/~woodward/ch754/str_cp.htm;) which should be experimental value.




Jianfeng

At 2015-10-19 13:09:01, "Babu" <mpb... at gmail.com> wrote:

hi, Jianfeng Jia,


Can you please describe how you define
      &CELL
       A     3.9239  0.0000000000000000E+00    0.0000000000000000E+00
       B     0.0000000000000000E+00    3.9239   0.0000000000000000E+00
       C     0.0000000000000000E+00    0.0000000000000000E+00    3.9239      these values for your pt atom.

On Sunday, 11 October 2015 12:44:08 UTC+5:30, jjf... at yahoo.com.cn wrote:
Dear All,


I am using CP2K to optimize the cell of Pt metal. The input is as below,
 &GLOBAL
   PRINT_LEVEL  LOW
   PROJECT_NAME Pt
   RUN_TYPE  CELL_OPT
 &END GLOBAL
 &MOTION
   &CELL_OPT
     OPTIMIZER  BFGS
     KEEP_SYMMETRY T
   &END CELL_OPT
 &END MOTION
 &FORCE_EVAL
   METHOD  QS
   STRESS_TENSOR  ANALYTICAL
   &DFT
     &SCF
       MAX_SCF  50
       EPS_SCF     9.9999999999999995E-10
        CHOLESKY  INVERSE
        ADDED_MOS 500
   &MIXING
   METHOD BROYDEN_MIXING
   ALPHA   0.1
   BETA    0.7
   NBROYDEN  8
   &END
   &SMEAR  ON
     METHOD FERMI_DIRAC
     ELECTRONIC_TEMPERATURE [K] 100
   &END SMEAR
   &DIAGONALIZATION T
   &END DIAGONALIZATION
     &END SCF
     &QS
       METHOD  GPW
       EPS_DEFAULT 1.0E-12
    EXTRAPOLATION USE_GUESS
     &END QS
     &MGRID
       CUTOFF     4.0000000000000000E+02
     &END MGRID
     &XC
       DENSITY_CUTOFF     1.0000000000000000E-10
       GRADIENT_CUTOFF     1.0000000000000000E-10
       TAU_CUTOFF     1.0000000000000000E-10
       &XC_FUNCTIONAL  NO_SHORTCUT
         &PBE  T
         &END PBE
       &END XC_FUNCTIONAL
       &VDW_POTENTIAL
         POTENTIAL_TYPE  PAIR_POTENTIAL
         &PAIR_POTENTIAL
           R_CUTOFF     9.0000000000000000E+00
           TYPE  DFTD3
           PARAMETER_FILE_NAME /lustre/home/jiajf/cp2k/dftd3.dat
           REFERENCE_FUNCTIONAL PBE
           EPS_CN     9.9999999999999995E-07
           CALCULATE_C9_TERM  T
           REFERENCE_C9_TERM  T
           LONG_RANGE_CORRECTION  T
           VERBOSE_OUTPUT  F
         &END PAIR_POTENTIAL
       &END VDW_POTENTIAL
     &END XC
     &POISSON
       POISSON_SOLVER  PERIODIC
       PERIODIC  XYZ
     &END POISSON
   &END DFT
   &SUBSYS
     &CELL
       A     3.9239  0.0000000000000000E+00    0.0000000000000000E+00
       B     0.0000000000000000E+00    3.9239   0.0000000000000000E+00
       C     0.0000000000000000E+00    0.0000000000000000E+00    3.9239
       PERIODIC  XYZ
       SYMMETRY CUBIC
      MULTIPLE_UNIT_CELL  4 4 4
     &END CELL
     &COORD
Pt  0.0000    0.0000    0.0000
Pt  0.0000    1.9620    1.9620
Pt  1.9620    0.0000    1.9620
Pt  1.9620    1.9620    0.0000
     &END COORD
     &KIND Pt
       BASIS_SET DZVP-MOLOPT-SR-GTH
       POTENTIAL GTH-PBE-q18
     &END KIND
     &TOPOLOGY
      MULTIPLE_UNIT_CELL  4 4 4
     &END TOPOLOGY
   &END SUBSYS
 &END FORCE_EVAL


It can achieve covegence smoothly after about 8 SCF-cycles. However, I found the energies from each SCF-cycle were below,
ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):           -30774.690068596093624
ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):           -30774.474988016871066
ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):           -30773.785173646669136
ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):           -30772.813279130394221
ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):           -30772.382090925824741
ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):           -30772.370917807555088
ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):           -30772.370406719932362
ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):           -30772.370389366384188


It is clearly that the optimzed cell has higher energy than the original cell. It is out of my understanding. Anyone can help?


Jianfeng Jia






 

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