Thanks for your reply!<div>The attached file is the result of a calculation, showing that the total force of the system is :<br />-------------------------------------------------------<div>....<br /> 189 2 H -0.02270940 -0.01715719 -0.01124088<br /> 190 2 H -0.00819690 0.01778486 -0.00220956<br /> 191 2 H -0.00491958 -0.00982567 0.00540266<br /> 192 2 H -0.00744376 0.00269638 -0.00803075<br /> SUM OF ATOMIC FORCES 0.00405273 -0.00782982 0.01173920 0.01468126</div><div>-------------------------------------------------------</div><div>The total force here is not particularly small, and it is comparable to the forces experienced by some H atoms. </div><div>Is this result reasonable, even considering the ripple effect?</div><div><br /></div><div>best wishes,</div><div><br /></div><div>Dongfei</div></div><br /><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Monday, 19 May 2025 at 21:26:00 UTC+8 Jürg Hutter 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
<br>
<br>inaccurate numerics can be a source for forces not summing up to zero. However, I assume
<br>(we don't know actually, as you don't share the forces) that the residual force is due to the
<br>'ripple effect'. CP2K uses aequidistant grids to calculate XC energies. For such grids there is no
<br>longer any translational invariance.
<br>
<br>regards
<br>JH
<br>
<br>________________________________________
<br>From: <a href data-email-masked rel="nofollow">cp...@googlegroups.com</a> <<a href data-email-masked rel="nofollow">cp...@googlegroups.com</a>> on behalf of liu dongfei <<a href data-email-masked rel="nofollow">liud...@gmail.com</a>>
<br>Sent: Monday, May 19, 2025 5:00 AM
<br>To: cp2k
<br>Subject: [CP2K:21474] The total force calculated by CP2K is not zero
<br>
<br>Hi all, I’m currently simulating a pure water system with CP2K. Despite configuring appropriate convergence criteria (e.g., CUTOFF, REL_CUTOFF, and EPS_SCF), the total forces from the calculation do not converge to zero. Attached is my input configuration.
<br>Could anyone provide insights into potential causes or recommend literature discussing this specific issue?
<br>Thanks in advance!
<br>
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