<div>As an update, I could figure it. With Eq (5) in the provided paper, the virial kinetic energies and the values which CP2K would be equal if for the term 3/2KT the temperature T is always almost a fixed value and equal to the temperature at which the simulation is done. <br></div><div>It means there should be some bug or different meaning for the temperature and kinetic energy which CP2K prints in the first three columns.</div><div><br></div><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Sunday, May 30, 2021 at 6:21:11 PM UTC+2 am...@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;"><br>
<p>Hi everyone,<span></span></p>
<p>In running some path integral MD simulation in cp2k I have observed
some strange issues and would be grateful if someone can comment on that.<span></span></p>
<p>After running the attached input script main.inp, the energy
terms are printed in a file named “md-01-energy-1.dat”. <span></span></p>
<p>The first issue which I encountered is that the kinetic
energy printed out in the third column can no way be related to the calculated temperatures
printed in the 5<span>th</span> column. Regardless of the degree of freedom and
unit conversion factors, at least there should be a correlation between them
which doesn’t exist here.<span></span></p>
<p>The second and more important issue: The calculated virial
kinetic energy which is printed in the fourth column of “md-01-energy-1.dat” file
also seems kind of strange. This value is calculated via the virial estimator written
as equation (5) in the attached pdf file. <span></span></p>
<p>To reproduce what CP2K prints, I manually calculated the second
term in right hand side of eq (5) using the position of the centroids and beads
printed out by the script and for the gradient of the potential energy required
by eq(5) I also used the forces which CP2K prints. <span></span></p>
<p>Something really surprising and unusual which I observed is
that the second term in right hand side of eq (5) which I manually calculated *before*
adding 3/2KT to it (as should be done based on the virial estimator) shows a
perfect correlation with the total virial kinetic energy which CP2K prints (R=1.00)
(although for this the virial kinetic energies which CP2K prints are ca. 438
times the values which I calculate and I couldn’t find the reason even with
trying various possible unit conversions). <span></span></p>
<p>If I also add the data I obtain with 3/2KT which should be
done to yield the total kinetic energies, then the correlation coefficient
dramatically reduced. <span></span></p>
<p>I would highly appreciate your comments/helps.<span></span></p>
<p>Best regards,<span></span></p>
<p>Amin<span></span></p>
<p><span> </span></p>
</blockquote></div>