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="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/8432682b-63da-4365-ac25-e53733f7e262n%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/8432682b-63da-4365-ac25-e53733f7e262n%40googlegroups.com</a>.