Conflict in parameters of unit cell after CELL_OPTIMIZATION

Matt W mattwa... at gmail.com
Wed Nov 15 16:42:10 CET 2017


I think your initial structure is strange (wrong). Check everything looks 
correct in an appropriate visualisation package - check all atoms are 
present, maybe some symmetry equivalent ones are missing, for instance.

Are you trying to make a slab, or bulk. Start with bulk.

Matt

On Wednesday, November 15, 2017 at 12:51:24 AM UTC, Amin wrote:
>
> I took the initial unit cell from VNL's crystallographic database for 
> Anatase TiO2 and then I made the initial unit cell for Anatase (101) slab. 
> I ran the calculation for Cell Optimization and finally got the results 
> that I mentioned already. Maybe the procedure that I'm employing for making 
> the initial unit cell is not correct?
>
>
>
> On Tuesday, November 14, 2017 at 11:02:29 PM UTC+1, Matt W wrote:
>>
>> Hi,
>>
>> I still don't really see anything very wrong with the setup (it is a bit 
>> inefficient, use smaller MAX_SCF in inner loop and FULL_ALL or 
>> FULL_SINGLE_INVERSE preconditioner).
>>
>> The initial structure seems very bad - are your coordinates/cell params 
>> correct? Perhaps you converge to a different polymorph or a local minima?
>>
>> Matt
>>
>> On Tuesday, November 14, 2017 at 12:14:09 PM UTC, Amin wrote:
>>>
>>> Hi Matt, 
>>>
>>> Thanks for the feedback.
>>> My results for a,b and c are 11.520*9.789*11.379 but the results in the 
>>> paper are 10.227*11.346*10.540 and yes my SCF converges. 
>>> I have tested with other structures but I couldn't achieve the same 
>>> results which have been done with the same criteria with CP2K. that's why I 
>>> thought there might be something wrong with my input file.
>>>
>>> Best,
>>>
>>> Amin
>>>
>>>
>>> On Tuesday, November 14, 2017 at 12:45:57 PM UTC+1, Matt W wrote:
>>>>
>>>> Hi,
>>>>
>>>> what do you mean when you say that the results don't agree? Massively 
>>>> wrong, or a small difference?
>>>>
>>>> Does your SCF converge? I don't see any very obvious problems with your 
>>>> input at a quick glance.
>>>>
>>>> Matt
>>>>
>>>> On Tuesday, November 14, 2017 at 11:43:16 AM UTC+1, Amin wrote:
>>>>>
>>>>> Dear all, 
>>>>> I'm having problem with my CELL_OPT calculations. I tried to achieve 
>>>>> lattice parameters for Anatase (101) unit cell but my results are very 
>>>>> different than the other results coming from literature. Specially the 
>>>>> results mentioned in the reference paper of this exercise: 
>>>>> https://www.cp2k.org/exercises:2015_pitt:gga
>>>>> I tried with/without the repetition of the unit cell but the final 
>>>>> lattice parameters was not consistent with those mentioned in literature.
>>>>> I would be grateful if someone takes a look to my input file and 
>>>>> reminds me what's wrong with my calculations. thanks.
>>>>>
>>>>> &GLOBAL
>>>>>   PROJECT cell3
>>>>>   RUN_TYPE CELL_OPT
>>>>>   PRINT_LEVEL LOW
>>>>>   EXTENDED_FFT_LENGTHS
>>>>> &END GLOBAL
>>>>>
>>>>> &FORCE_EVAL
>>>>>   METHOD Quickstep
>>>>>   STRESS_TENSOR ANALYTICAL
>>>>>   &DFT
>>>>>     BASIS_SET_FILE_NAME ./BASIS_MOLOPT
>>>>>     POTENTIAL_FILE_NAME ./GTH_POTENTIALS
>>>>>     UKS
>>>>>     WFN_RESTART_FILE_NAME s-RESTART.wfn
>>>>>     MULTIPLICITY 1
>>>>>     &QS
>>>>>       METHOD GPW
>>>>>     &END QS
>>>>>     &MGRID
>>>>>       CUTOFF 800
>>>>>       REL_CUTOFF 60
>>>>>     &END MGRID
>>>>>     &SCF
>>>>>       EPS_SCF 1.0E-6
>>>>>       MAX_SCF 150
>>>>>       &OUTER_SCF
>>>>>         EPS_SCF 1.0E-6
>>>>>         MAX_SCF 40
>>>>>       &END
>>>>>       &OT
>>>>>         PRECONDITIONER FULL_SINGLE
>>>>>         MINIMIZER CG
>>>>>       &END OT
>>>>>       SCF_GUESS ATOMIC
>>>>>     &END SCF
>>>>>     &XC
>>>>>       &XC_FUNCTIONAL PBE
>>>>>       &END XC_FUNCTIONAL
>>>>>       &vdW_POTENTIAL
>>>>>         DISPERSION_FUNCTIONAL PAIR_POTENTIAL
>>>>>         &PAIR_POTENTIAL
>>>>>           TYPE DFTD3(BJ)
>>>>>           REFERENCE_FUNCTIONAL PBE
>>>>>           CALCULATE_C9_TERM .FALSE.
>>>>>           PARAMETER_FILE_NAME ./dftd3.dat
>>>>>           R_CUTOFF 15.0
>>>>>         &END PAIR_POTENTIAL
>>>>>       &END vdW_POTENTIAL
>>>>>     &END XC
>>>>>     &PRINT
>>>>>       &HIRSHFELD
>>>>>         SELF_CONSISTENT .TRUE.
>>>>>       &END HIRSHFELD
>>>>>     &END PRINT
>>>>>     &POISSON
>>>>>       PERIODIC XYZ
>>>>>       POISSON_SOLVER PERIODIC
>>>>>     &END POISSON
>>>>>   &END DFT
>>>>>     
>>>>>   &SUBSYS
>>>>>     &CELL
>>>>>       ABC 10.2394 3.7845 3.513
>>>>>       PERIODIC XYZ
>>>>>       MULTIPLE_UNIT_CELL 1 3 3 
>>>>>     &END CELL
>>>>>     &TOPOLOGY
>>>>>             MULTIPLE_UNIT_CELL 1 3 3
>>>>>     &END TOPOLOGY
>>>>>     &COORD
>>>>>       @INCLUDE 'cell3.coord'
>>>>>     &END COORD
>>>>>     &KIND O
>>>>>       BASIS_SET DZVP-MOLOPT-GTH
>>>>>       POTENTIAL GTH-PBE-q6
>>>>>     &END KIND
>>>>>     &KIND Ti
>>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH
>>>>>       POTENTIAL GTH-PBE-q12
>>>>>     &END KIND
>>>>>   &END SUBSYS
>>>>> &END FORCE_EVAL
>>>>>
>>>>> &MOTION
>>>>>   &GEO_OPT
>>>>>     TYPE MINIMIZATION
>>>>>     OPTIMIZER BFGS
>>>>>   &END GEO_OPT
>>>>>   &CELL_OPT
>>>>>           KEEP_SYMMETRY TRUE
>>>>>           KEEP_ANGLES   TRUE
>>>>>   &END        
>>>>> &END MOTION
>>>>>
>>>>> cell3.coord:
>>>>>
>>>>> O     7.692165e-01 -3.336155e-17  1.170579e+00    0.07512 -0.00000  
>>>>> 0.33321
>>>>> O     5.888893e+00  1.892250e+00  1.170579e+00    0.57512  0.50000  
>>>>> 0.33321
>>>>> Ti    4.049520e+00  1.892250e+00  1.902225e+00    0.39549  0.50000  
>>>>> 0.54148
>>>>> Ti    9.169196e+00 -3.976756e-16  1.902225e+00    0.89549 -0.00000  
>>>>> 0.54148
>>>>> O     3.678746e+00 -1.595502e-16  2.049708e+00    0.35928 -0.00000  
>>>>> 0.58346
>>>>> O     8.798422e+00  1.892250e+00  2.049708e+00    0.85928  0.50000  
>>>>> 0.58346
>>>>> O     2.210147e+00  1.892250e+00  2.633872e+00    0.21585  0.50000  
>>>>> 0.74975
>>>>> O     7.329824e+00 -3.179005e-16  2.633872e+00    0.71585 -0.00000  
>>>>> 0.74975
>>>>> Ti    1.839373e+00 -7.977512e-17  2.781355e+00    0.17964 -0.00000  
>>>>> 0.79173
>>>>> Ti    6.959049e+00  1.892250e+00  2.781355e+00    0.67964  0.50000  
>>>>> 0.79173
>>>>> O     0.000000e+00  0.000000e+00  3.513001e+00    0.00000  0.00000  
>>>>> 1.00000
>>>>> O     5.119676e+00  1.892250e+00  3.513001e+00    0.50000  0.50000  
>>>>> 1.00000
>>>>>
>>>>>
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