[CP2K-user] [CP2K:16521] Re: IR spectm for NaCl under PBC

fabia...@gmail.com fabianducry at gmail.com
Fri Jan 28 12:42:08 UTC 2022


Dear Viktor,

Several things:
 - If you choose RUN_TYPE GEO_OPT then you should have MOTION&GEO_OPT and 
not MOTION&CELL_OPT and vice versa.
 - Set EPS_DEFAULT to 1e-12
 - For CELL_OPT: you should have a &CELL_REF section with dimensions 
approx. 1.3-1.5 times larger (test this!) than &CELL
 - You need MULTIPLE_UNIT_CELL in &CELL_REF too

Cheers,
Fabian

On Friday, 28 January 2022 at 09:30:16 UTC+1 volk... at gmail.com wrote:

> Dear Fabian:
> good morning.
>
> According to your notice
> I redefined MAX_FORCE to be under 
> &MOTION
>    &CELL_OPT
> However, the cp2k failed convergence - energy was just oscillating.
>
> After studying your replies to other members,
> I did two changes in the input.
>
> 1.
> While keeping the definitions in 
> &MOTION
>    &CELL_OPT
> ....
> in GLOBAL 
> I changed to
>  RUN_TYPE GEO_OPT
>
> The logic of the guess is that apparently &CELL_OPT can not lead.
> Then, may be, 
> GEO should lead, while CELL should be set to follow.
>
> It is not clear, if under such setting STRESS TENSOR would have any 
> meaning.
> Perhaps it has not role no more and becomes redundant.
>
> 2. 
> Also, I introduced 
> CELL_REF
>
> I attach the input.
> This is the job I am testing.
>
> Would you have a minute to comment, criticize - I be thankful.
>
> In any way, 
> thank you for your time, 
> and nice weekend
> :-)
> Best!
> Victor
>
>   
>
> On Thu, Jan 27, 2022 at 2:30 PM fabia... at gmail.com <fabia... at gmail.com> 
> wrote:
>
>> cp2k works just fine and does everything you tell it to do. The issue is 
>> that you specified MAX_FORCE 1.0E-07  etc. for &GEO_OPT instead of 
>> &CELL_OPT...
>>
>> On Thursday, 27 January 2022 at 11:39:21 UTC+1 volk... at gmail.com wrote:
>>
>>> Dear Fabian:
>>> Dear Dr. Hutter:
>>>
>>> is it possible that CP2K is present not to follow the input instructons?
>>>
>>> *According to my instructions (pleas, see attached)*
>>> *in the MOTION section there are instructions*
>>>     MAX_DR    8.0E-07
>>>     RMS_DR    4.0E-07    
>>>     MAX_FORCE 1.0E-07
>>>     RMS_FORCE 1.0E-08
>>>
>>>
>>> *but *
>>> *as Fabian has noticed:*
>>>
>>> The output you attached shows for step 28:
>>>   Max. gradient              =         0.0002958006
>>>   Conv. limit for gradients  =         0.0004500000
>>>   Conv. in gradients         =                  YES
>>>
>>> So that output is for MAX_FORCE 4.5E-4 and not 1.0E-7. You should also 
>>> decrease EPS_SCF (to 1e-7 or 1e-8) and probably EPS_DEFAULT.
>>>
>>>
>>> *Is it possible that there is a bug *
>>> *that prevents a certain level of precision?*
>>>
>>> Thank you.
>>> With best regards.
>>>
>>> Victor
>>>
>>>
>>>
>>>
>>> On Thu, Jan 27, 2022 at 12:00 PM fabia... at gmail.com <fabia... at gmail.com> 
>>> wrote:
>>>
>>>> Dear Viktor,
>>>>
>>>> The output you attached shows for step 28:
>>>>   Max. gradient              =         0.0002958006
>>>>   Conv. limit for gradients  =         0.0004500000
>>>>   Conv. in gradients         =                  YES
>>>>
>>>> So that output is for MAX_FORCE 4.5E-4 and not 1.0E-7. You should also 
>>>> decrease EPS_SCF (to 1e-7 or 1e-8) and probably EPS_DEFAULT.
>>>>
>>>> Fabian
>>>>
>>>> On Wednesday, 26 January 2022 at 21:12:03 UTC+1 volk... at gmail.com 
>>>> wrote:
>>>>
>>>>> Dear Fabian:
>>>>> please forgive me
>>>>>
>>>>> *If I set*
>>>>>     OPTIMIZER BFGS
>>>>>
>>>>>     MAX_DR    8.0E-06
>>>>>     RMS_DR    4.0E-06    
>>>>>     MAX_FORCE 1.0E-06
>>>>>     RMS_FORCE 1.0E-07
>>>>> *then the forces are*
>>>>> ATOMIC FORCES in [a.u.] 
>>>>>  # Atom   Kind   Element          X              Y              Z
>>>>>       1      1      Na          0.00000796     0.00000796     
>>>>> 0.00000796
>>>>>       2      1      Na          0.00000796     0.00001127     
>>>>> 0.00001127
>>>>>       3      1      Na          0.00001127     0.00000796     
>>>>> 0.00001127
>>>>>       4      1      Na          0.00001127     0.00001127     
>>>>> 0.00000796
>>>>>       5      2      Cl          0.00000052     0.00000052     
>>>>> 0.00000052
>>>>>       6      2      Cl          0.00000052     0.00000052     
>>>>> 0.00000052
>>>>>       7      2      Cl          0.00000052     0.00000052     
>>>>> 0.00000052
>>>>>       8      2      Cl          0.00000052     0.00000052     
>>>>> 0.00000052
>>>>>  SUM OF ATOMIC FORCES           0.00004056     0.00004056     
>>>>> 0.00004056     0.00007026
>>>>>
>>>>> *and the soectrum is terrible (please, see the attached xxx_F.out)*
>>>>>
>>>>> *Then I try to instruct more strict convregence by*
>>>>>     OPTIMIZER BFGS
>>>>>     MAX_DR    8.0E-07
>>>>>     RMS_DR    4.0E-07    
>>>>>     MAX_FORCE 1.0E-07
>>>>>     RMS_FORCE 1.0E-08
>>>>>
>>>>> *but the forces deteriorate*
>>>>> ATOMIC FORCES in [a.u.]
>>>>>  # Atom   Kind   Element          X              Y              Z
>>>>>       1      1      Na          0.00009945     0.00009945     
>>>>> 0.00009945
>>>>>       2      1      Na          0.00025879    -0.00001513   
>>>>>  -0.00001513
>>>>>       3      1      Na         -0.00001519     0.00025872   
>>>>>  -0.00001518
>>>>>       4      1      Na         -0.00001513    -0.00001513     
>>>>> 0.00025879
>>>>>       5      2      Cl          0.00031492     0.00004422     
>>>>> 0.00004422
>>>>>       6      2      Cl          0.00024177     0.00024177     
>>>>> 0.00024177
>>>>>       7      2      Cl          0.00004422     0.00004422     
>>>>> 0.00031492
>>>>>       8      2      Cl          0.00004422     0.00031492     
>>>>> 0.00004422
>>>>>  SUM OF ATOMIC FORCES           0.00097305     0.00097303     
>>>>> 0.00097305     0.00168536
>>>>>
>>>>> *I attach the optimization inp and out pair.*
>>>>> *I donot see what is wrong?*
>>>>>
>>>>> *May be GPW and BFGS are not for such optimizations?   *
>>>>> *Thank you.*
>>>>> *Victor*
>>>>>
>>>>>
>>>>>
>>>>> On Mon, Jan 24, 2022 at 4:22 PM fabia... at gmail.com <fabia... at gmail.com> 
>>>>> wrote:
>>>>>
>>>>>> Dear Victor,
>>>>>>
>>>>>> You need a much tighter convergence criterion for the optimization 
>>>>>> prior to the vibrational analysis. You increased MAX_FORCE to 5e-3 
>>>>>> (guessing from the output), instead you have to decrease it to at least 
>>>>>> 1e-5, maybe even lower.
>>>>>> CP2K prints the forces for the replica in the output. The forces 
>>>>>> under "Minimum Structure - Energy and Forces:" should be more or less 0 and 
>>>>>> considerably differ between the other images. Currently you are 
>>>>>> computing the vibrational analysis from almost pure noise. 
>>>>>>
>>>>>> Cheers,
>>>>>> Fabian
>>>>>> On Sunday, 23 January 2022 at 19:58:05 UTC+1 volk... at gmail.com wrote:
>>>>>>
>>>>>>> Dear colleagues:
>>>>>>> here is the normal mode analysis I could manage by now for NaCl 
>>>>>>> under PBC.
>>>>>>>
>>>>>>> There is only one unit cell: previously, I reported that I could not 
>>>>>>> configure CP2K to reproduce NaCl structure using multiple cells 2 2 2.
>>>>>>> There are strange distortions, which I did confirm to sustain under 
>>>>>>> different CUTOFF values (1000 and 600), and regardless if dispersion is 
>>>>>>> switched off or not.
>>>>>>>
>>>>>>> When a single cell under PBC, optimization leads to the “right” 
>>>>>>> structure, when ESP 10^-12.
>>>>>>>
>>>>>>> However, the negative(imaginary) frequencies are many and they are 
>>>>>>> very large.
>>>>>>> I may anticipate that the “miss performance” is enhanced due to the 
>>>>>>> PBC.
>>>>>>>
>>>>>>> Eventhough the results are "devastating",
>>>>>>> :-)
>>>>>>> nonetheless, I find this might be very good, very helpful – I got an 
>>>>>>> idea.
>>>>>>>
>>>>>>> Dear Dr. Hutter,
>>>>>>> is it possible that CP2K may have an “issue” about positioning a 
>>>>>>> structure 
>>>>>>> in respect to both, in respect to the FT grind and in respect to the 
>>>>>>> PBC.
>>>>>>> Perhaps, there could be a relative mismatch phenomenon, which could 
>>>>>>> stimulate artificial transition states with negative frequencies?
>>>>>>>
>>>>>>> May be, what I observe is that PBC on the unit cell helps to sense 
>>>>>>> this better?
>>>>>>>
>>>>>>>
>>>>>>> Thank you for your time and for any comments.
>>>>>>>
>>>>>>> With best regards,
>>>>>>> Sincerely
>>>>>>> Victor
>>>>>>>
>>>>>> -- 
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