Hybrid functional calculation results show large difference with VASP
Nico Holmberg
holmbe... at gmail.com
Tue Sep 19 05:26:43 UTC 2017
Hi,
You should try switching off ADMM purification i.e. setting
ADMM_PURIFICATION_METHOD NONE. According to the implementation paper, this
is the correct way to obtain MO energies. A direct quote from the
implementation paper: "In order to use the eigenvalues of the ADMM
Kohn-Sham matrix directly as orbital energies, e.g., to calculate the band
gaps of a system, an ADMM scheme without purification needs to be
employed."
You can find TZVP-MOLOPT quality basis sets for Ag, Cs, and In in the
BASIS_MOLOPT_UCL
<https://github.com/cp2k/cp2k/blob/master/cp2k/data/BASIS_MOLOPT_UCL> file
distributed with the trunk version of cp2k if you want to test the effect
of using larger primary basis sets.
BR,
Nico
maanantai 18. syyskuuta 2017 18.31.50 UTC+3 Xiaoming Wang kirjoitti:
>
> 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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