Hybrid functional calculation results show large difference with VASP
Xiaoming Wang
wxia... at gmail.com
Tue Sep 19 05:44:01 UTC 2017
Hi, Nico,
Thanks for your reply.
I did tried the case without ADMM_PURIFICATION, but the band gap is only
0.01 eV smaller. As for the basis set, I don't know whether it would affect
the HFX electronic structure or not. But for GW calculations, the
completeness of the basis set plays an important role. I will try the TZVP
basis to see what happens.
Best,
Xiaoming
On Tuesday, September 19, 2017 at 1:26:43 AM UTC-4, Nico Holmberg wrote:
>
> 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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