[CP2K:4550] Bulk modulus of silicon with CP2K
Süle Péter
su... at mfa.kfki.hu
Mon Aug 12 13:09:57 UTC 2013
Dear Leila,
Is that necessary to use dispersion correction for
bulk modulus calculation of Si ?
In your submitted input file vdw is included:
� � � &vdW_POTENTIAL
� � � � �DISPERSION_FUNCTIONAL PAIR_POTENTIAL
� � � � �&PAIR_POTENTIAL
� � � � � � TYPE DFTD3
� � � � � � CALCULATE_C9_TERM .TRUE.
� � � � � � REFERENCE_C9_TERM .TRUE.
� � � � � � LONG_RANGE_CORRECTION .TRUE.
� � � � � � PARAMETER_FILE_NAME ./dftd3.dat
I'm not sure, but it could influence the PBE results.
Best regard, P�ter S�le
On Mon, 12 Aug 2013, leila salimi wrote:
> Dear�Juerg,�
> Thanks for your answer.
> 1) the PBE value for B is 89 GPa.
> 2) I also tried with higher cutoff and REF_CUTOFF, but it didn't change.
>
> &MGRID
> � � � NGRIDS 8
> � � � CUTOFF 500
> � � � REL_CUTOFF �60
> � � &END MGRID
>
>
> On Mon, Aug 12, 2013 at 2:40 PM, <hut... at pci.uzh.ch> wrote:
> Hi
>
> two things to do:
> 1) What is the official PBE value for this quantity?
> 2) Use a REF_CELL and a high enough cutoff (has to be tested)
> � �in order to get a smooth enough pressure curve
>
> regards
>
> Juerg
>
> --------------------------------------------------------------
> Juerg Hutter � � � � � � � � � � � � Phone : ++41 44 635 4491
> Physical Chemistry Institute � FAX � : ++41 44 635 6838
> University of Zurich � � � � � � � E-mail: �hut... at pci.uzh.ch
> Winterthurerstrasse 190
> CH-8057 Zurich, Switzerland
> ---------------------------------------------------------------
>
> -----cp... at googlegroups.com wrote: -----
> To: cp... at googlegroups.com
> From: leila
> Sent by: cp... at googlegroups.com
> Date: 08/12/2013 11:57AM
> Subject: [CP2K:4549] Bulk modulus of silicon with CP2K
>
> Hi all,�
>
> I simulated the silicon with 64 atoms and calculated the
> energy-volume plot and fitted with murnaghan.
> I found the lattice parameter 5.48 A ( lattice parameter in
> experiment is 5.44 A), That is OK but the bulk modulus is 63 GPa
> that is very low. (B_exp = 100 GPa)
> I really don' t know why cp2k gets B so low???
>
> I tried with DZVP basis set and PBE functional with 280 Ryd cut
> off for density.
> I also checked with TZVP, it is not changing so much. It is 66
> GPa.
> Can anybody help me with that?
> You can find my inputfile in below.
>
> &GLOBAL
> � PROJECT si64-10.88A
> � PRINT_LEVEL LOW
> � RUN_TYPE GEO_OPT
> &END GLOBAL
> &MOTION
> � &CELL_OPT
> � � TYPE GEO_OPT
> � � OPTIMIZER CG
> � � MAX_ITER 20
> � � EXTERNAL_PRESSURE [bar] 1.0
> � � MAX_DR 0.02
> � � RMS_DR 0.01
> � � MAX_FORCE 0.0002
> � � RMS_FORCE 0.0001
> � � KEEP_ANGLES
> � � &CG
> � � � &LINE_SEARCH
> � � � � TYPE 2PNT
> � � � � &2PNT
> � � � � &END
> � � � &END
> � � &END
> � &END
> � &GEO_OPT
> � � MAX_ITER 200
> � � MINIMIZER BFGS
> � &END
> � &PRINT
> � � &STRESS
> � � &END STRESS
> � � &RESTART
> � � � &EACH
> � � � � CELL_OPT 1
> � � � &END
> � � &END
> � &END
> &END
> &FORCE_EVAL
> � METHOD QS
> � STRESS_TENSOR ANALYTICAL
> � &DFT
> � � BASIS_SET_FILE_NAME ./BASIS_MOLOPT
> � � POTENTIAL_FILE_NAME ./GTH_POTENTIALS
> � � &MGRID
> � � � CUTOFF 280
> � � &END MGRID
> � � &QS
> � � � METHOD GPW
> � � &END QS
> � � &SCF
> � � � SCF_GUESS RESTART
> � � � MAX_SCF 20
> � � � EPS_SCF 1.0e-5
> � � � &OUTER_SCF
> � � � EPS_SCF 1.0E-5
> � � � &END
> � � � &OT ON
> # � � � �MINIMIZER DIIS
> � � � � �ROTATION
> � � � &END OT
> � � � &PRINT
> � � � � &RESTART
> � � � � � BACKUP_COPIES 0
> � � � � &END RESTART
> � � � &END PRINT
> � � &END SCF
> � � &XC
> � � � &XC_FUNCTIONAL PBE
> � � � &END XC_FUNCTIONAL
> � � � &vdW_POTENTIAL
> � � � � �DISPERSION_FUNCTIONAL PAIR_POTENTIAL
> � � � � �&PAIR_POTENTIAL
> � � � � � � TYPE DFTD3
> � � � � � � CALCULATE_C9_TERM .TRUE.
> � � � � � � REFERENCE_C9_TERM .TRUE.
> � � � � � � LONG_RANGE_CORRECTION .TRUE.
> � � � � � � PARAMETER_FILE_NAME ./dftd3.dat
> � � � � � � REFERENCE_FUNCTIONAL PBE
> � � � � � � R_CUTOFF 8.
> � � � � � � EPS_CN 0.01
> � � � � �&END PAIR_POTENTIAL
> � � � &END vdW_POTENTIAL
> � � &END XC
> � &END DFT
> � &SUBSYS
> � � &TOPOLOGY
> � � � COORD_FILE_NAME ./GEOMETRY.xyz
> � � � COORDINATE XYZ
> # � � �CONNECTIVITY OFF
> � � &END TOPOLOGY
> � � &KIND Si
> � � � BASIS_SET DZVP-MOLOPT-SR-GTH
> # � � �BASIS_SET SZV-MOLOPT-SR-GTH
> # � � � BASIS_SET TZVP-MOLOPT-GTH
> � � � POTENTIAL GTH-PBE-q4
> � � &END
> � � &CELL
> � � � ABC � �10.88 �10.88 10.88
> � � &END
> � &END SUBSYS
> �&END
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