[CP2K-user] [CP2K:18195] Re: CELL_OPT

alberto albesantonocito at gmail.com
Wed Dec 14 09:17:01 UTC 2022


Thank you for your answer,

I launched a new calculation with the most optimized geometry of the 
previous calculation.
After 67 steps the calculation did not converge.
Furthermore, the trend is fluctuating, in fact, looking at each step, the 
energy and internal pressure values are not slowly converging.
I think there is some error in the input

Some example steps:

--------  Informations at step =    20 ------------
  Optimization Method        =                 BFGS
  Total Energy               =     -2786.7149770620
  Internal Pressure [bar]    =       -56.1292626124
  Real energy change         =        -0.0000281887
  Predicted change in energy =        -0.0000241958
  Scaling factor             =         0.0000000000
  Step size                  =         0.0023312228
  Trust radius               =         0.4724315332
  Decrease in energy         =                  YES
  Used time                  =             1345.608

  Convergence check :
  Max. step size             =         0.0023312228
  Conv. limit for step size  =         0.0030000000
  Convergence in step size   =                  YES
  RMS step size              =         0.0006823469
  Conv. limit for RMS step   =         0.0015000000
  Convergence in RMS step    =                  YES
  Max. gradient              =         0.0014732410
  Conv. limit for gradients  =         0.0004500000
  Conv. for gradients        =                   NO
  RMS gradient               =         0.0001678103
  Conv. limit for RMS grad.  =         0.0003000000
  Conv. in RMS gradients     =                  YES
  Pressure Deviation [bar]   =       -57.1425126124
  Pressure Tolerance [bar]   =       100.0000000000
  Conv. for  PRESSURE        =                  YES

 --------  Informations at step =    21 ------------
  Optimization Method        =                 BFGS
  Total Energy               =     -2786.7149979500
  Internal Pressure [bar]    =     -2209.5678997974
  Real energy change         =        -0.0000208880
  Predicted change in energy =        -0.0000138917
  Scaling factor             =         0.0000000000
  Step size                  =         0.0022754833
  Trust radius               =         0.4724315332
  Decrease in energy         =                  YES
  Used time                  =             1376.350

  Convergence check :
  Max. step size             =         0.0022754833
  Conv. limit for step size  =         0.0030000000
  Convergence in step size   =                  YES
  RMS step size              =         0.0005998616
  Conv. limit for RMS step   =         0.0015000000
  Convergence in RMS step    =                  YES
  Max. gradient              =         0.0101103659
  Conv. limit for gradients  =         0.0004500000
  Conv. for gradients        =                   NO
  RMS gradient               =         0.0005961090
  Conv. limit for RMS grad.  =         0.0003000000
  Conv. for gradients        =                   NO
  Pressure Deviation [bar]   =     -2210.5811497974
  Pressure Tolerance [bar]   =       100.0000000000
  Conv. for  PRESSURE        =                   NO
 ---------------------------------------------------

--------  Informations at step =    22 ------------
  Optimization Method        =                 BFGS
  Total Energy               =     -2786.6713087460
  Internal Pressure [bar]    =     48434.3786931764
  Real energy change         =         0.0436892040
  Predicted change in energy =        -4.2905769783
  Scaling factor             =         0.0050059206
  Step size                  =         0.4724315332
  Trust radius               =         0.4724315332
  Decrease in energy         =                   NO
  Used time                  =             1158.309

  Convergence check :
  Max. step size             =         0.4724315332
  Conv. limit for step size  =         0.0030000000
  Convergence in step size   =                   NO
  RMS step size              =         0.0286236623
  Conv. limit for RMS step   =         0.0015000000
  Convergence in RMS step    =                   NO
  Max. gradient              =         0.1387194513
  Conv. limit for gradients  =         0.0004500000
  Conv. for gradients        =                   NO
  RMS gradient               =         0.0080861893
  Conv. limit for RMS grad.  =         0.0003000000
  Conv. for gradients        =                   NO
  Pressure Deviation [bar]   =     48433.3654431764
  Pressure Tolerance [bar]   =       100.0000000000
  Conv. for  PRESSURE        =                   NO

....

 --------  Informations at step =    66 ------------
  Optimization Method        =                 BFGS
  Total Energy               =     -2786.7149997788
  Internal Pressure [bar]    =       401.0551035482
  Real energy change         =        -0.0024535793
  Predicted change in energy =        -0.0019705816
  Scaling factor             =         0.5030910593
  Step size                  =         0.0799790567
  Trust radius               =         0.4724315332
  Decrease in energy         =                   NO
  Used time                  =             1241.233

  Convergence check :
  Max. step size             =         0.0799790567
  Conv. limit for step size  =         0.0030000000
  Convergence in step size   =                   NO
  RMS step size              =         0.0074265499
  Conv. limit for RMS step   =         0.0015000000
  Convergence in RMS step    =                   NO
  Max. gradient              =         0.0047190415
  Conv. limit for gradients  =         0.0004500000
  Conv. for gradients        =                   NO
  RMS gradient               =         0.0003199135
  Conv. limit for RMS grad.  =         0.0003000000
  Conv. for gradients        =                   NO
  Pressure Deviation [bar]   =       400.0418535482
  Pressure Tolerance [bar]   =       100.0000000000
  Conv. for  PRESSURE        =                   NO
 ---------------------------------------------------

Thanks

Alberto

Il giorno domenica 11 dicembre 2022 alle 15:06:38 UTC+1 Marcella Iannuzzi 
ha scritto:

> Hi ?
>
> If energy and internal pressure are slowly converging to a minimum, 
> probably you need to run more iterations
> Regards
> Marcella
>
> On Saturday, December 10, 2022 at 12:36:45 PM UTC+1 alberto wrote:
>
>> Hello cp2k users,
>> I want to study a crystal of YAG (Y3Al5O12) doped with Yb3 +.
>>
>> The cation Yb(III) tends to replace Y(III), since the two cations have 
>> very similar ionic radii.
>> Hence Yb (III)   occupies the dodecahedral sites of the crystal.
>> However, in the scientific literature it is hypothesized that a small 
>> percentage of doping Yb(III)   can occupy the octahedral sites, i.e. 
>> Yb(III)   replaces Al(III)   cations.
>> This hypothesis is supported by recent spectroscopic evidence. The 
>> experimental data are present in the article 
>> https://doi.org/10.1016/j.jssc.2022.123577
>>
>> To simulate the distortions of the structure when Yb(III) occupies an 
>> octahedral site I started from the YAG cubic cell containing 160 atoms and 
>> replaced an octahedral Al(III) with Yb(III).
>>
>> I managed to optimize the structure with the LDA functional, while with 
>> the PBE functional after 53 cycles the calculation did not converge.
>>
>> I would like to optimize the structure with PBE to subsequently perform a 
>> pDos calculation and find the splitting of the 4f orbitals of Yb(III) when 
>> it is in the octahedral site and see if they are comparable with those 
>> shown in the image below
>> [image: Yb_YAG_splitting_orbitals.jpg]
>> What can I improve in the input or what is wrong??
>>
>> I share input and post the final part of output (file too big)
>>
>>  
>>
>>  !-----------------------------------------------------------------------------!
>>
>>  ENERGY| Total FORCE_EVAL ( QS ) energy [a.u.]:           
>>  -2786.715103466123765
>>
>>  ENERGY| Total FORCE_EVAL ( QS ) energy [a.u.]:           
>>  -2786.715103466123765
>>
>>  --------  Informations at step =    55 ------------
>>   Optimization Method        =                 BFGS
>>   Total Energy               =     -2786.7151034661
>>   Internal Pressure [bar]    =      -804.8902015897
>>   Real energy change         =        -0.0000086535
>>   Predicted change in energy =        -0.0000022936
>>   Scaling factor             =         0.0309001301
>>   Step size                  =         0.0011175379
>>   Trust radius               =         0.4724315332
>>   Decrease in energy         =                   NO
>>   Used time                  =             1219.940
>>
>>   Convergence check :
>>   Max. step size             =         0.0011175379
>>   Conv. limit for step size  =         0.0030000000
>>   Convergence in step size   =                  YES
>>   RMS step size              =         0.0001385820
>>   Conv. limit for RMS step   =         0.0015000000
>>   Convergence in RMS step    =                  YES
>>   Max. gradient              =         0.0037177331
>>   Conv. limit for gradients  =         0.0004500000
>>   Conv. for gradients        =                   NO
>>   RMS gradient               =         0.0002540531
>>   Conv. limit for RMS grad.  =         0.0003000000
>>   Conv. in RMS gradients     =                  YES
>>   Pressure Deviation [bar]   =      -805.9034515897 <(903)%20451-5897>
>>   Pressure Tolerance [bar]   =       100.0000000000
>>   Conv. for  PRESSURE        =                   NO
>>  ---------------------------------------------------
>>  Estimated peak process memory after this step [MiB]                     
>>    1354
>>
>> Thank you
>>
>

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