Thanks for reminding me! Yes I only remember the total energy is variational and for orbital energy I am not quite sure. <div> </div><div>Yike</div><div class="gmail_quote"><div dir="auto" class="gmail_attr">在2024年7月12日星期五 UTC+8 15:50:25<Jürg Hutter> 写道： </div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hi on what grounds you expect the orbital energies to be variational? Only the total KS energy will have this property. 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 Yike Huang <<a href data-email-masked rel="nofollow">ykhua...@gmail.com</a>> Sent: Thursday, July 11, 2024 12:34 PM To: cp2k Subject: [CP2K:20444] Why does the energy of the lowest band not decrease monotonously when increasing size of basis sets? Dear all, I am working on testing excitation of very simple molecules such as Ag dimer, and examining both occupied and unoccupied states calculated. However, I find when I change the basis from SVP to TZVPP, the energy of the lowest band increases a littble bit, then decreases if I furtherly change to QZVPP basis (all basis are from BASIS_MOLOPT_UZH collection, I set CUTOFF to 600 Ry, REL_CUTOFF 30 Ry): basis SVP TZVPP QZVPP e(1) -96.3005 -95.3219 -96.1675 energies are in eV. To my knowledge if the completeness of basis set increases, the energy should be lower. I also convert the pseudopotential to UPF file (by CP2K ATOM module) and perform pw calculation with Quantum ESPRESSO, I set the kinetic energy cutoff to 300 Ry but still find the energy is higher than any of what I obtained from CP2K. But in principle pw is a very huge basis set, so I get confused again... basis PW e(1) -94.8071 Very best wishes, Yike -- 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/aac93697-0423-4daa-be25-37bb7f7fbb52n%40googlegroups.com" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=zh-CN&q=https://groups.google.com/d/msgid/cp2k/aac93697-0423-4daa-be25-37bb7f7fbb52n%2540googlegroups.com&source=gmail&ust=1720869633958000&usg=AOvVaw3mT7adkimzNSLWaOsLpvuA">https://groups.google.com/d/msgid/cp2k/aac93697-0423-4daa-be25-37bb7f7fbb52n%40googlegroups.com</a><<a href="https://groups.google.com/d/msgid/cp2k/aac93697-0423-4daa-be25-37bb7f7fbb52n%40googlegroups.com?utm_medium=email&utm_source=footer" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=zh-CN&q=https://groups.google.com/d/msgid/cp2k/aac93697-0423-4daa-be25-37bb7f7fbb52n%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1720869633958000&usg=AOvVaw142gAKKyQtLJvejRv8Y67_">https://groups.google.com/d/msgid/cp2k/aac93697-0423-4daa-be25-37bb7f7fbb52n%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/b2960183-085c-4a50-9948-b49444cbfbcfn%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/b2960183-085c-4a50-9948-b49444cbfbcfn%40googlegroups.com</a>.