Dear Prof. Hutter, Thank you very much for the clarification. I presume that it cannot be expected that a simple "switching off" of the dispersion part (commenting out the entire vdW_POTENTIAL block and re-running a single-point calculation with the same combination of exchange and correlation functionals) would not give a physically meaningful estimation of the dispersion contribution (as the difference between "full" rev-vdW-DF2 energy and the "exchange-corellation only" energy), because some part of the local contribution is implicitly included in the exchange-correlation part. Or could that be a plausible option? Thanks again, best regards, Michael <div class="gmail_quote"><div dir="auto" class="gmail_attr">Jürg Hutter schrieb am Montag, 16. Oktober 2023 um 11:08:42 UTC+2: </div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hi the printed dispersion energy is the calculated energy of the non-local vdW energy functional (only the non-local part!). Together with the XC energy you get the full functional energy. No other information is available. regards JH ________________________________________ 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 Michael Fischer <<a href data-email-masked rel="nofollow">doktor...@gmail.com</a>> Sent: Friday, October 13, 2023 10:16 AM To: cp2k Subject: [CP2K:19362] Isolate dispersion contribution in vdW-DF2 calculations Dear all, I am studying host-guest systems (molecules in zeolites) with the rev-vdW-DF2 functional (X_B86_R, PW92 correlation, LMKLL dispersion) and I am looking at the possibility to calculate the dispersion contribution to the total interaction energy. In the past, I have used Grimme-type dispersion correction, e.g., PBE-D3. Here, it was fairly trivial to calculate the dispersion contribution as: E_disp = E_disp(host+guest) - E_disp(host) - E_disp(guest) ...where the E_disp terms on the right-hand side correspond to the energy values given in the line "Dispersion energy" in the CP2K output. With rev-vdW-DF2, "Dispersion energy" is also printed. However, what is notable in the first place is that the dispersion energy is always positive. A subtraction as in the above equation gives results that look plausible at first, but a comparison to the total interaction energies shows that the E_disp contribution is sometimes more negative than E_tot, something which seems implausible. Is there some way to isolate the dispersion contribution in calculations using non-local vdW-DF approximations? Any suggestion will be highly appreciated! Thank you and best regards, Michael -- You received this message because you are subscribed to the Google Groups "cp2k" group. To unsubscribe from this group and stop receiving emails from it, send an email to <a href data-email-masked rel="nofollow">cp2k+uns...@googlegroups.com</a><mailto:<a href data-email-masked rel="nofollow">cp2k+uns...@googlegroups.com</a>>. To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/8432682b-63da-4365-ac25-e53733f7e262n%40googlegroups.com" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=de&q=https://groups.google.com/d/msgid/cp2k/8432682b-63da-4365-ac25-e53733f7e262n%2540googlegroups.com&source=gmail&ust=1697533740900000&usg=AOvVaw2WvZkgz34ynw8IUuSwPlNt">https://groups.google.com/d/msgid/cp2k/8432682b-63da-4365-ac25-e53733f7e262n%40googlegroups.com</a><<a href="https://groups.google.com/d/msgid/cp2k/8432682b-63da-4365-ac25-e53733f7e262n%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=de&q=https://groups.google.com/d/msgid/cp2k/8432682b-63da-4365-ac25-e53733f7e262n%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1697533740900000&usg=AOvVaw0dhCbMQkE-PhF_NjhCaadh">https://groups.google.com/d/msgid/cp2k/8432682b-63da-4365-ac25-e53733f7e262n%40googlegroups.com?utm_medium=email&utm_source=footer</a>>. </blockquote></div> -- You received this message because you are subscribed to the Google Groups "cp2k" group. To unsubscribe from this group and stop receiving emails from it, send an email to <a href="mailto:cp2k+unsubscribe@googlegroups.com">cp2k+unsubscribe@googlegroups.com</a>. To view this discussion on the web visit <a href="https://groups.google.com/d/msgid/cp2k/97f8688a-52b4-47f2-98cb-6733be1a2a9cn%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/97f8688a-52b4-47f2-98cb-6733be1a2a9cn%40googlegroups.com</a>.