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<p>Dear Imane,</p>
<p>the NEB algorithm assumes that you are starting and ending from a
stable state, i.e. a local minimum of the total energy as a
function of the ionic coordinates. The dat file should contain
energies relative to the minimum of the two extremes, so if they
are negative, either the assumption does not hold, or you have
discovered a third local minimum that is lower than those you
knew.</p>
<p>kind regards</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 2/16/26 16:04, imane BEZZAOUI wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAP32B6YZZdCpA9YOCcgEjJUR_MkFie580LnrdAkgas6pLabQ=w@mail.gmail.com">
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<div> </div>
<div><span
style="color:rgb(0,0,0);font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:16px">Dear
Quantum Espresso users,</span></div>
<div><span
style="color:rgb(0,0,0);font-family:Aptos,Aptos_EmbeddedFont,Aptos_MSFontService,Calibri,Helvetica,sans-serif;font-size:16px"><br>
</span></div>
<div> I am performing a NEB calculation using <code>neb.x</code>
in Quantum ESPRESSO to study hydrogen diffusion (35 atoms,
10 images).</div>
<div><br>
</div>
<div>
<li>
<p>1-The NEB path does not converge.</p>
</li>
<li>
<p>2- The <code>*.dat</code> file shows negative values for
the relative energies.</p>
</li>
<li>
<p>Any advice or suggestions would be greatly appreciated.</p>
<p>
</p>
<p>Thank you in advance.</p>
</li>
</div>
</div>
<br>
<fieldset class="moz-mime-attachment-header"></fieldset>
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<div class="moz-signature">-- <br>
<small>Dr. Lorenzo Paulatto<br>
IR IMPMC - CNRS UMR 7590 / Sorbonne Université / MNHN <br>
phone: +33 (0)1 442 79822 / telegram: lpaulatto<br>
<a href="http://people.impmc.fr/lpaulatto/">people.impmc.fr/lpaulatto</a>
- <a href="https://anharmonic.github.io/">anharmonic.github.io</a><br>
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