Conflict in parameters of unit cell after CELL_OPTIMIZATION

Amin amin.jaf... at gmail.com
Wed Nov 15 01:51:24 CET 2017


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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