Hybrid functional calculation results show large difference with VASP
Xiaoming Wang
wxia... at gmail.com
Mon Sep 18 15:31:50 UTC 2017
Hi Marcella,
Thanks for your reply. I have checked that parameter. Actually, eps_schwarz
of 1.0e-10 give quite a small improvement of the band gap, ~0.01 eV. Any
other suggestions?
Best,
Xiaoming
On Monday, September 18, 2017 at 11:18:58 AM UTC-4, Marcella Iannuzzi wrote:
>
> Hi,
>
> Your eps_schwarz at 1.0e-6 is far too large.
> The default is 1.0e-10.
>
> Regards
> Marcella
>
> On Monday, September 18, 2017 at 5:07:21 PM UTC+2, Xiaoming Wang wrote:
>>
>> Hello,
>>
>> I conducted PBE0 and HSE calculations on a cube of ~10*10*10
>> (perovskite). For comparison, I also did the calculations using VASP (gamma
>> only). However, to my surprise, the band gap obtained by cp2k is about 0.5
>> eV (HSE) and 0.8 eV(PBE0) smaller than by vasp. The vasp results agree
>> well with literature. For the cp2k calculations, I have checked the
>> convergence of the cutoffs and auxiliary basis sets. Since for my
>> structure, the only available basis sets is DZVP within BASIS_MOLOPT, thus
>> I could not find a way to increase the primary basis size. But I checked
>> the PBE results with DZVP compared with those of VASP. The difference of
>> the band gap is very small, say only 0.02 eV. So I think the DZVP basis set
>> is OK for my system. The inputs of my calculations are as follows. Could
>> anyone give me some suggestions?
>>
>> HSE input:
>> --------------------------------------------------------------------
>> &GLOBAL
>> PROJECT_NAME CsInAgCl
>> RUN_TYPE ENERGY
>> PRINT_LEVEL LOW
>> &END GLOBAL
>>
>> &FORCE_EVAL
>> METHOD QS
>> &DFT
>> BASIS_SET_FILE_NAME BASIS_MOLOPT
>> BASIS_SET_FILE_NAME BASIS_ADMM
>> BASIS_SET_FILE_NAME BASIS_ADMM_MOLOPT
>> POTENTIAL_FILE_NAME GTH_POTENTIALS
>> WFN_RESTART_FILE_NAME -PBE.wfn
>> &QS
>> EPS_PGF_ORB 1.0e-6
>> &END
>> &MGRID
>> CUTOFF 250
>> REL_CUTOFF 60
>> &END MGRID
>> &XC
>> &XC_FUNCTIONAL
>> &PBE
>> SCALE_X 0.0
>> SCALE_C 1.0
>> &END PBE
>> &XWPBE
>> SCALE_X -0.25
>> SCALE_X0 1.0
>> OMEGA 0.11
>> &END XWPBE
>> &END XC_FUNCTIONAL
>> &HF
>> FRACTION 0.25
>> &SCREENING
>> EPS_SCHWARZ 1.0e-6
>> &END SCREENING
>> &INTERACTION_POTENTIAL
>> POTENTIAL_TYPE SHORTRANGE
>> OMEGA 0.11
>> &END INTERACTION_POTENTIAL
>> &MEMORY
>> MAX_MEMORY 2400
>> EPS_STORAGE_SCALING 0.1
>> &END MEMORY
>> &END HF
>> &END XC
>> &SCF
>> #ADDED_MOS 2
>> MAX_SCF 100
>> EPS_SCF 1.0e-6
>> CHOLESKY INVERSE
>> SCF_GUESS RESTART
>> &OT
>> PRECONDITIONER FULL_ALL
>> ENERGY_GAP 0.01
>> &END OT
>> &END SCF
>> &AUXILIARY_DENSITY_MATRIX_METHOD
>> METHOD BASIS_PROJECTION
>> ADMM_PURIFICATION_METHOD MO_DIAG
>> &END AUXILIARY_DENSITY_MATRIX_METHOD
>> &PRINT
>> &MO_CUBES
>> WRITE_CUBE F
>> NHOMO 1
>> NLUMO 1
>> &END MO_CUBES
>> &END PRINT
>> &END DFT
>> &SUBSYS
>> &CELL
>> ABC [angstrom] 10.5345 10.5345 10.5345
>> ALPHA_BETA_GAMMA [deg] 90 90 90
>> PERIODIC XYZ
>> SYMMETRY CUBIC
>> &END CELL
>> &COORD
>> ....[I omitted the coors here ]
>> SCALED T
>> &END COORD
>> &KIND Cs
>> ELEMENT Cs
>> BASIS_SET DZVP-MOLOPT-SR-GTH
>> AUX_FIT_BASIS_SET FIT11
>> POTENTIAL GTH-PBE-q9
>> &END KIND
>> &KIND In
>> ELEMENT In
>> BASIS_SET DZVP-MOLOPT-SR-GTH
>> AUX_FIT_BASIS_SET FIT11
>> POTENTIAL GTH-PBE-q13
>> &END KIND
>> &KIND Ag
>> ELEMENT Ag
>> BASIS_SET DZVP-MOLOPT-SR-GTH
>> AUX_FIT_BASIS_SET FIT11
>> POTENTIAL GTH-PBE-q11
>> &END KIND
>> &KIND Cl
>> ELEMENT Cl
>> BASIS_SET DZVP-MOLOPT-SR-GTH
>> AUX_FIT_BASIS_SET FIT3
>> POTENTIAL GTH-PBE-q7
>> &END KIND
>> &END SUBSYS
>> &END FORCE_EVAL
>>
>> -----------------------------------------------------------------------------------------------
>>
>> PBE0 input
>>
>>
>> --------------------------------------------------------
>> &GLOBAL
>> PROJECT_NAME CsInAgCl
>> RUN_TYPE ENERGY
>> PRINT_LEVEL LOW
>> &END GLOBAL
>> &FORCE_EVAL
>> METHOD QS
>> &DFT
>> BASIS_SET_FILE_NAME BASIS_MOLOPT
>> BASIS_SET_FILE_NAME BASIS_ADMM
>> BASIS_SET_FILE_NAME BASIS_ADMM_MOLOPT
>> POTENTIAL_FILE_NAME GTH_POTENTIALS
>> WFN_RESTART_FILE_NAMEPBE.wfn
>> &QS
>> EPS_PGF_ORB 1.0e-6
>> &END
>> &MGRID
>> CUTOFF 250
>> REL_CUTOFF 60
>> &END MGRID
>> &XC
>> &XC_FUNCTIONAL
>> &PBE
>> SCALE_X 0.75
>> SCALE_C 1.0
>> &END PBE
>> &PBE_HOLE_T_C_LR
>> CUTOFF_RADIUS 5.25
>> SCALE_X 0.25
>> &END PBE_HOLE_T_C_LR
>> &END XC_FUNCTIONAL
>> &HF
>> FRACTION 0.25
>> &SCREENING
>> EPS_SCHWARZ 1.0e-6
>> &END SCREENING
>> &INTERACTION_POTENTIAL
>> POTENTIAL_TYPE TRUNCATED
>> CUTOFF_RADIUS 5.25
>> T_C_G_DATA ./t_c_g.dat
>> &END INTERACTION_POTENTIAL
>> &MEMORY
>> MAX_MEMORY 2400
>> EPS_STORAGE_SCALING 0.1
>> &END MEMORY
>> &END HF
>> &END XC
>> &SCF
>> MAX_SCF 100
>> EPS_SCF 1.0e-6
>> CHOLESKY INVERSE
>> SCF_GUESS RESTART
>> &OT
>> PRECONDITIONER FULL_ALL
>> ENERGY_GAP 0.01
>> &END OT
>> &END SCF
>> &AUXILIARY_DENSITY_MATRIX_METHOD
>> METHOD BASIS_PROJECTION
>> ADMM_PURIFICATION_METHOD MO_DIAG
>> &END AUXILIARY_DENSITY_MATRIX_METHOD
>> &PRINT
>> &MO_CUBES
>> WRITE_CUBE F
>> NHOMO 1
>> NLUMO 1
>> &END MO_CUBES
>> &END PRINT
>> &END DFT
>> &SUBSYS
>> &CELL
>> ABC [angstrom] 10.5345 10.5345 10.5345
>> ALPHA_BETA_GAMMA [deg] 90 90 90
>> PERIODIC XYZ
>> SYMMETRY CUBIC
>> &END CELL
>> &COORD
>> .......
>> SCALED T
>> &END COORD
>> &KIND Cs
>> ELEMENT Cs
>> BASIS_SET DZVP-MOLOPT-SR-GTH
>> AUX_FIT_BASIS_SET FIT11
>> POTENTIAL GTH-PBE-q9
>> &END KIND
>> &KIND In
>> ELEMENT In
>> BASIS_SET DZVP-MOLOPT-SR-GTH
>> AUX_FIT_BASIS_SET FIT11
>> POTENTIAL GTH-PBE-q13
>> &END KIND
>> &KIND Ag
>> ELEMENT Ag
>> BASIS_SET DZVP-MOLOPT-SR-GTH
>> AUX_FIT_BASIS_SET FIT11
>> POTENTIAL GTH-PBE-q11
>> &END KIND
>> &KIND Cl
>> ELEMENT Cl
>> BASIS_SET DZVP-MOLOPT-SR-GTH
>> AUX_FIT_BASIS_SET FIT3
>> POTENTIAL GTH-PBE-q7
>> &END KIND
>> &END SUBSYS
>> &END FORCE_EVAL
>>
>> --------------------------------------
>>
>>
>>
>>
>> Best,
>>
>> Xiaoming Wang
>>
>>
>>
>>
>
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