<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Dear Amin, <div class=""><br class=""></div><div class="">using the centroid viral estimator you compute the correct quantum kinetic energy. I suspect </div><div class="">that in the ener file the classical kinetic energy or the difference to the quantum kinetic energy </div><div class="">is printed. See for instance Eq. 23 of the appended paper. Also, let me add that the effective </div><div class="">temperature is P*T, where P is the number of beads … </div><div class=""><br class=""></div><div class="">Best, </div><div class="">Thomas</div><div class=""><br class=""></div><div class="">P.S. <a href="https://journals.aps.org/pre/abstract/10.1103/PhysRevE.93.043305" class="">https://journals.aps.org/pre/abstract/10.1103/PhysRevE.93.043305</a><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">Am 31.05.2021 um 14:51 schrieb amin....@<a href="http://gmail.com" class="">gmail.com</a> <<a href="mailto:amin....@gmail.com" class="">amin....@gmail.com</a>>:</div><br class="Apple-interchange-newline"><div class=""><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">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.<span class="Apple-converted-space"> </span><br class=""></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">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 style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><br class=""></div><br style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><div class="gmail_quote" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><div dir="auto" class="gmail_attr">On Sunday, May 30, 2021 at 6:21:11 PM UTC+2 amin....@<a href="http://gmail.com/" class="">gmail.com</a><span class="Apple-converted-space"> </span>wrote:<br class=""></div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><br class=""><p class="">Hi everyone,<span class=""></span></p><p class="">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 class=""></span></p><p class="">After running the attached input script main.inp, the energy terms are printed in a file named “md-01-energy-1.dat”.<span class="Apple-converted-space"> </span><span class=""></span></p><p class="">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 class="">th</span><span class="Apple-converted-space"> </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 class=""></span></p><p class="">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 class="Apple-converted-space"> </span><span class=""></span></p><p class="">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 class="Apple-converted-space"> </span><span class=""></span></p><p class="">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 class="Apple-converted-space"> </span><span class=""></span></p><p class="">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 class="Apple-converted-space"> </span><span class=""></span></p><p class="">I would highly appreciate your comments/helps.<span class=""></span></p><p class="">Best regards,<span class=""></span></p><p class="">Amin<span class=""></span></p><div class=""><span class=""> </span><br class="webkit-block-placeholder"></div></blockquote></div><div style="caret-color: rgb(0, 0, 0); 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