<div>Dear Wei,</div><div><br></div><div>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.</div><div><br></div><div>Best,</div><div>Fabian<br></div><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Saturday, 14 November 2020 at 00:15:01 UTC+1 we...@gmail.com wrote:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hi Fabian,<div><br></div><div>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.</div><div><br></div><div>Wei<br><br><br></div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Friday, November 13, 2020 at 2:25:51 AM UTC-5 <a href data-email-masked rel="nofollow">fa...@gmail.com</a> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>Hi,</div><div><br></div><div>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.</div><div><br></div><div>Best,</div><div>Fabian<br></div><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Friday, 13 November 2020 at 04:27:44 UTC+1 <a rel="nofollow">we...@gmail.com</a> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><p>I was playing
with the neb tutorial at <a href="https://www.cp2k.org/exercises:2016_uzh_cmest:path_optimization_neb" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=en-GB&q=https://www.cp2k.org/exercises:2016_uzh_cmest:path_optimization_neb&source=gmail&ust=1605426428712000&usg=AFQjCNFiQWor7-RA_12Nn4HLoNygPrMnRA">https://www.cp2k.org/exercises:2016_uzh_cmest:path_optimization_neb</a> and was using all input files from this site.</p>
<p> </p>
<p>After the
second band step, the separate band output gave the following convergence
check:</p>
<p>*******************************************************************************</p>
<p> RMS DISPLACEMENT = 0.01661
[ 0.00010]
( NO)</p>
<p> MAX DISPLACEMENT = 0.04582
[ 0.00020]
( NO)</p>
<p> RMS FORCE =
0.00459 [ 0.00500] (YES)</p>
<p> MAX FORCE =
0.02442 [ 0.00100] ( NO)</p>
<p> *******************************************************************************</p>
<p> </p>
<p><b>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.</b></p>
<p> </p>
<p> NEB| Computing Energies and Forces</p>
<p> NEB| REPLICA Nr. 1- Energy and Forces</p>
<p> NEB| Total
Energy: -14.955972284</p>
<p> NEB|
ATOM
X Y Z</p>
<p> NEB|
C
-0.000158132 -0.000000000 -0.000010247 </p>
<p> NEB|
C
0.000158132 0.000000000 0.000010247 </p>
<p> NEB|
H
-0.000009893 -0.000000000 0.000090633 </p>
<p> NEB|
H -0.000044050 -0.000068824 -0.000011886 </p>
<p> NEB|
H
-0.000044050 0.000068824 -0.000011886 </p>
<p> NEB|
H
0.000009893 0.000000000 -0.000090633 </p>
<p> NEB|
H 0.000044050 0.000068824 0.000011886 </p>
<p> NEB|
H
0.000044050 -0.000068824 0.000011886 </p>
<p> NEB| REPLICA Nr. 2- Energy and Forces</p>
<p> NEB| Total Energy: -14.953424807</p>
<p> NEB|
ATOM
X Y Z</p>
<p> NEB|
C
0.015511582 -0.000123867 -0.000363499 </p>
<p> NEB|
C
-0.015514484 0.000198863 0.000377792 </p>
<p> NEB|
H
0.000857207 0.000192596 0.003925016 </p>
<p> NEB|
H
0.000684401 -0.003902176 -0.002099542 </p>
<p> NEB|
H
0.000794070 0.003497209 -0.002176137 </p>
<p> NEB|
H
-0.000859132 0.000183216 -0.003909916 </p>
<p> NEB|
H
-0.000734015 0.003669315 0.002258834 </p>
<p> NEB|
H
-0.000739709 -0.003761630 0.001987922 </p>
<p> NEB| REPLICA Nr. 3- Energy and Forces</p>
<p> NEB| Total
Energy: -14.952203598</p>
<p> NEB|
ATOM
X Y Z</p>
<p> NEB|
C
0.010538684 -0.000238117 -0.000516915 </p>
<p> NEB|
C
-0.010542876 0.000214692 0.000522403 </p>
<p> NEB|
H
0.000413313 -0.000291891 0.003136219 </p>
<p> NEB|
H
0.000191793 -0.002982635 -0.002211249 </p>
<p> NEB|
H
0.000330883 0.003013668 -0.001368350 </p>
<p> NEB|
H
-0.000425288 -0.000291342 -0.003075548 </p>
<p> NEB|
H
-0.000246337 0.003274227 0.001455731 </p>
<p> NEB|
H
-0.000260278 -0.002823871 0.002056329 </p>
<p> NEB| REPLICA Nr. 4- Energy and Forces</p>
<p> NEB| Total
Energy: -14.951836807</p>
<p> NEB|
ATOM
X Y Z</p>
<p> NEB|
C
-0.000166119 -0.000233856 -0.000487654 </p>
<p> NEB|
C
0.000160984 0.000258427 0.000483064 </p>
<p> NEB|
H
0.000029046 0.000183156 0.000057179 </p>
<p> NEB|
H
-0.000172411 -0.000483736 -0.000359493 </p>
<p> NEB|
H
-0.000023827 0.000096042 -0.000156766 </p>
<p> NEB|
H
-0.000040779 0.000199584 0.000032287 </p>
<p> NEB|
H
0.000106393 0.000381211 0.000225999 </p>
<p> NEB|
H
0.000106826 -0.000345313 0.000203051 </p>
<p> NEB| REPLICA Nr. 5- Energy and Forces</p>
<p> NEB| Total
Energy: -14.951407301</p>
<p> NEB|
ATOM X Y Z</p>
<p> NEB|
C
0.015874406 -0.000326490 -0.000555730 </p>
<p> NEB|
C
-0.015842202 0.000299497 0.000559685 </p>
<p> NEB|
H 0.000535731 -0.002915118 0.002845326 </p>
<p> NEB|
H
0.000312063 -0.001213868 -0.004546885 </p>
<p> NEB|
H
0.000505489 0.003928930 0.001110436 </p>
<p> NEB|
H -0.000585448 -0.002832671 -0.002713428 </p>
<p> NEB|
H
-0.000406024 0.004307148 -0.001105774 </p>
<p> NEB|
H
-0.000394296 -0.001114621 0.004405311 </p>
<p> NEB| REPLICA Nr. 6- Energy and Forces</p>
<p> NEB| Total
Energy: -14.952232632</p>
<p> NEB|
ATOM
X Y Z</p>
<p> NEB|
C
0.024362977 -0.000274819 -0.000383546 </p>
<p> NEB|
C
-0.024281416 0.000284322 0.000400750 </p>
<p> NEB|
H
0.001292285 -0.004167767 0.002626455 </p>
<p> NEB|
H 0.001137983 -0.000313475 -0.005288164 </p>
<p> NEB|
H
0.001311947 0.004206108 0.002313869 </p>
<p> NEB|
H
-0.001362979 -0.004056262 -0.002510384 </p>
<p> NEB|
H
-0.001240025 0.004537593 -0.002369052 </p>
<p> NEB|
H
-0.001219620 -0.000261211 0.005209053 </p>
<p> NEB| REPLICA Nr. 7- Energy and Forces</p>
<p> NEB| Total
Energy: -14.954539124</p>
<p> NEB|
ATOM
X Y Z</p>
<p> NEB|
C
0.016039728 -0.000166622 -0.000179795 </p>
<p> NEB|
C
-0.015936746 0.000181883 0.000203661 </p>
<p> NEB|
H
0.000838326 -0.004015114 0.002084504 </p>
<p> NEB|
H
0.000753054 0.000204003 -0.004717897 </p>
<p> NEB|
H
0.000870997 0.003741728 0.002384503 </p>
<p> NEB|
H
-0.000902028 -0.003947288 -0.002036799 </p>
<p> NEB|
H
-0.000843340 0.003959916 -0.002460137 </p>
<p> NEB|
H
-0.000819474 0.000224363 0.004721034 </p>
<p> NEB| REPLICA Nr. 8- Energy and Forces</p>
<p> NEB|
Total
Energy: -14.955953570</p>
<p> NEB|
ATOM
X Y Z</p>
<p> NEB|
C
-0.000000797 0.000124456 0.000066034 </p>
<p> NEB|
C 0.000011951 -0.000146750 -0.000118626 </p>
<p> NEB|
H
0.000029286 0.000146761 0.000101230 </p>
<p> NEB|
H
-0.000005088 -0.000168487 -0.000042189 </p>
<p> NEB|
H
0.000005136 0.000121871 -0.000047943 </p>
<p> NEB|
H
-0.000007405 -0.000110873 -0.000237047 </p>
<p> NEB|
H
-0.000035252 0.000164078 0.000019902 </p>
<p> NEB|
H
-0.000000769 -0.000171696 0.000257590</p></blockquote></div></blockquote></div></blockquote></div>