[CP2K-user] Trying to understand the output from neb(band) module

fa...@gmail.com fabia... at gmail.com
Sat Nov 14 07:52:45 UTC 2020


Dear Wei,

The force acting on an atom is a vector. The net force is equal to the 
length of this vector which is computed as the norm, not a simple sum.

Best,
Fabian

On Saturday, 14 November 2020 at 00:15:01 UTC+1 we... at gmail.com wrote:

> Hi Fabian,
>
> Thanks for the clarification.  What you pointed out makes sense.  However, 
> I wonder if that was the best way to control convergence.  Let's say your 
> x, y, z forces are 0.1 -0.1 0.001.  The net force will be 0.001.  If the 
> max force is set to be 0.002 in the convergence control, this looks fine 
> but we probably shouldn't say the force is converged.
>
> Wei
>
>
> On Friday, November 13, 2020 at 2:25:51 AM UTC-5 fa... at gmail.com wrote:
>
>> Hi,
>>
>> The the force on the first atom of replica Nr. 6 has the components 
>> 0.024362977  -0.000274819  -0.000383546, which results in a net force of 
>> 0.0244. This is precisely what is reported by cp2k.
>>
>> Best,
>> Fabian
>>
>> On Friday, 13 November 2020 at 04:27:44 UTC+1 we... at gmail.com wrote:
>>
>>> I was playing with the neb tutorial at 
>>> https://www.cp2k.org/exercises:2016_uzh_cmest:path_optimization_neb  
>>> and was using all input files from this site.
>>>
>>>  
>>>
>>> After the second band step, the separate band output gave the following 
>>> convergence check:
>>>
>>>
>>> *******************************************************************************
>>>
>>>  RMS DISPLACEMENT =   0.01661     [ 
>>> 0.00010]                               ( NO)
>>>
>>>  MAX DISPLACEMENT =   0.04582     [ 
>>> 0.00020]                               ( NO)
>>>
>>>  RMS FORCE        =   0.00459     [ 
>>> 0.00500]                               (YES)
>>>
>>>  MAX FORCE        =   0.02442     [ 
>>> 0.00100]                               ( NO)
>>>
>>>
>>>  *******************************************************************************
>>>
>>>  
>>>
>>> *The screen output has the following energies and force values.  What is 
>>> odd that the max force of all these images is not 0.02442.  Actually there 
>>> is no force that is close to be +-0.0244.  I am wondering what is this “MAX 
>>> FORCE”. Thanks.*
>>>
>>>  
>>>
>>>  NEB| Computing Energies and Forces
>>>
>>>  NEB| REPLICA Nr.    1- Energy and Forces
>>>
>>>  NEB|                                     Total Energy:            
>>> -14.955972284
>>>
>>>  NEB|    ATOM                            X                
>>> Y                Z
>>>
>>>  NEB|      C                      -0.000158132     -0.000000000     
>>> -0.000010247           
>>>
>>>  NEB|      C                       0.000158132      0.000000000      
>>> 0.000010247           
>>>
>>>  NEB|      H                      -0.000009893     -0.000000000      
>>> 0.000090633           
>>>
>>>  NEB|      H                      -0.000044050     -0.000068824     
>>> -0.000011886           
>>>
>>>  NEB|      H                      -0.000044050      0.000068824     
>>> -0.000011886           
>>>
>>>  NEB|      H                       0.000009893      0.000000000     
>>> -0.000090633           
>>>
>>>  NEB|      H                       0.000044050      0.000068824      
>>> 0.000011886           
>>>
>>>  NEB|      H                       0.000044050     -0.000068824      
>>> 0.000011886           
>>>
>>>  NEB| REPLICA Nr.    2- Energy and Forces
>>>
>>>  NEB|                                     Total Energy:            
>>> -14.953424807
>>>
>>>  NEB|    ATOM                            X                
>>> Y                Z
>>>
>>>  NEB|      C                       0.015511582     -0.000123867     
>>> -0.000363499           
>>>
>>>  NEB|      C                      -0.015514484      0.000198863      
>>> 0.000377792           
>>>
>>>  NEB|      H                       0.000857207      0.000192596      
>>> 0.003925016           
>>>
>>>  NEB|      H                       0.000684401     -0.003902176     
>>> -0.002099542           
>>>
>>>  NEB|      H                       0.000794070      0.003497209     
>>> -0.002176137           
>>>
>>>  NEB|      H                      -0.000859132      0.000183216     
>>> -0.003909916           
>>>
>>>  NEB|      H                      -0.000734015      0.003669315      
>>> 0.002258834           
>>>
>>>  NEB|      H                      -0.000739709     -0.003761630      
>>> 0.001987922           
>>>
>>>  NEB| REPLICA Nr.    3- Energy and Forces
>>>
>>>  NEB|                                     Total Energy:            
>>> -14.952203598
>>>
>>>  NEB|    ATOM                            X                
>>> Y                Z
>>>
>>>  NEB|      C                       0.010538684     -0.000238117     
>>> -0.000516915           
>>>
>>>  NEB|      C                      -0.010542876      0.000214692      
>>> 0.000522403           
>>>
>>>  NEB|      H                       0.000413313     -0.000291891      
>>> 0.003136219           
>>>
>>>  NEB|      H                       0.000191793     -0.002982635     
>>> -0.002211249           
>>>
>>>  NEB|      H                       0.000330883      0.003013668     
>>> -0.001368350           
>>>
>>>  NEB|      H                      -0.000425288     -0.000291342     
>>> -0.003075548           
>>>
>>>  NEB|      H                      -0.000246337      0.003274227      
>>> 0.001455731           
>>>
>>>  NEB|      H                      -0.000260278     -0.002823871      
>>> 0.002056329           
>>>
>>>  NEB| REPLICA Nr.    4- Energy and Forces
>>>
>>>  NEB|                                     Total Energy:            
>>> -14.951836807
>>>
>>>  NEB|    ATOM                            X                
>>> Y                Z
>>>
>>>  NEB|      C                      -0.000166119     -0.000233856     
>>> -0.000487654           
>>>
>>>  NEB|      C                       0.000160984      0.000258427      
>>> 0.000483064           
>>>
>>>  NEB|      H                       0.000029046      0.000183156      
>>> 0.000057179           
>>>
>>>  NEB|      H                      -0.000172411     -0.000483736     
>>> -0.000359493           
>>>
>>>  NEB|      H                      -0.000023827      0.000096042 
>>>     -0.000156766           
>>>
>>>  NEB|      H                      -0.000040779      0.000199584      
>>> 0.000032287           
>>>
>>>  NEB|      H                       0.000106393      0.000381211      
>>> 0.000225999           
>>>
>>>  NEB|      H                       0.000106826     -0.000345313      
>>> 0.000203051           
>>>
>>>  NEB| REPLICA Nr.    5- Energy and Forces
>>>
>>>  NEB|                                     Total Energy:            
>>> -14.951407301
>>>
>>>  NEB|    ATOM                            X                
>>> Y                Z
>>>
>>>  NEB|      C                       0.015874406     -0.000326490     
>>> -0.000555730           
>>>
>>>  NEB|      C                      -0.015842202      0.000299497      
>>> 0.000559685           
>>>
>>>  NEB|      H                       0.000535731     -0.002915118      
>>> 0.002845326           
>>>
>>>  NEB|      H                       0.000312063     -0.001213868     
>>> -0.004546885           
>>>
>>>  NEB|      H                       0.000505489      0.003928930      
>>> 0.001110436           
>>>
>>>  NEB|      H                      -0.000585448     -0.002832671     
>>> -0.002713428           
>>>
>>>  NEB|      H                      -0.000406024      0.004307148     
>>> -0.001105774           
>>>
>>>  NEB|      H                      -0.000394296     -0.001114621      
>>> 0.004405311           
>>>
>>>  NEB| REPLICA Nr.    6- Energy and Forces
>>>
>>>  NEB|                                     Total Energy:            
>>> -14.952232632
>>>
>>>  NEB|    ATOM                            X                
>>> Y                Z
>>>
>>>  NEB|      C                       0.024362977     -0.000274819     
>>> -0.000383546           
>>>
>>>  NEB|      C                      -0.024281416      0.000284322      
>>> 0.000400750           
>>>
>>>  NEB|      H                       0.001292285     -0.004167767      
>>> 0.002626455           
>>>
>>>  NEB|      H                       0.001137983     -0.000313475     
>>> -0.005288164           
>>>
>>>  NEB|      H                       0.001311947      0.004206108      
>>> 0.002313869           
>>>
>>>  NEB|      H                      -0.001362979     -0.004056262     
>>> -0.002510384           
>>>
>>>  NEB|      H                      -0.001240025      0.004537593     
>>> -0.002369052           
>>>
>>>  NEB|      H                      -0.001219620     -0.000261211      
>>> 0.005209053           
>>>
>>>  NEB| REPLICA Nr.    7- Energy and Forces
>>>
>>>  NEB|                                     Total Energy:            
>>> -14.954539124
>>>
>>>  NEB|    ATOM                            X                
>>> Y                Z
>>>
>>>  NEB|      C                       0.016039728     -0.000166622     
>>> -0.000179795           
>>>
>>>  NEB|      C                      -0.015936746      0.000181883      
>>> 0.000203661           
>>>
>>>  NEB|      H                       0.000838326     -0.004015114      
>>> 0.002084504           
>>>
>>>  NEB|      H                       0.000753054      0.000204003     
>>> -0.004717897           
>>>
>>>  NEB|      H                       0.000870997      0.003741728      
>>> 0.002384503           
>>>
>>>  NEB|      H                      -0.000902028     -0.003947288     
>>> -0.002036799           
>>>
>>>  NEB|      H                      -0.000843340      0.003959916     
>>> -0.002460137           
>>>
>>>  NEB|      H                      -0.000819474      0.000224363      
>>> 0.004721034           
>>>
>>>  NEB| REPLICA Nr.    8- Energy and Forces
>>>
>>>  NEB|                                     Total Energy:            
>>> -14.955953570
>>>
>>>  NEB|    ATOM                            X                
>>> Y                Z
>>>
>>>  NEB|      C                      -0.000000797      0.000124456      
>>> 0.000066034           
>>>
>>>  NEB|      C                       0.000011951     -0.000146750     
>>> -0.000118626           
>>>
>>>  NEB|      H                       0.000029286      0.000146761      
>>> 0.000101230           
>>>
>>>  NEB|      H                      -0.000005088     -0.000168487     
>>> -0.000042189           
>>>
>>>  NEB|      H                       0.000005136      0.000121871     
>>> -0.000047943           
>>>
>>>  NEB|      H                      -0.000007405     -0.000110873     
>>> -0.000237047           
>>>
>>>  NEB|      H                      -0.000035252      0.000164078     
>>>  0.000019902           
>>>
>>>  NEB|      H                      -0.000000769     -0.000171696      
>>> 0.000257590
>>>
>>
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