<p style="margin: 16px 0px; color: rgb(15, 17, 21); font-family: quote-cjk-patch, Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif; font-size: 16px;">Hello,<p style="margin: 16px 0px; color: rgb(15, 17, 21); font-family: quote-cjk-patch, Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif; font-size: 16px;"> I am using CP2K 2026.2 to compute the adsorption energy of H₂O on a CuAl₂O₄ slab. The system contains 227 atoms (224-atom slab + 3-atom H₂O) with <span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">PERIODIC XY, DZVP-MOLOPT-SR-GTH, PBE+D3(BJ), UKS, MULTIPLICITY 33, and U_eff = 3.0 eV on Cu 3d (<span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">L 2). Only the three H₂O atoms are free, giving 9 degrees of freedom.<p style="margin: 16px 0px; color: rgb(15, 17, 21); font-family: quote-cjk-patch, Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif; font-size: 16px;">Two problems:<ol start="1" style="margin: 16px 0px; padding-left: 18px; color: rgb(15, 17, 21); font-family: quote-cjk-patch, Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif; font-size: 16px;"><li>The warning <span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">DFT+U energy contribution is negative appears throughout. The <span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">&PLUS_U output shows single-spin d occupations of 9.3–10.4, whereas the physical limit is 5. The total spin is stable at 32.0 and S² = 272.1 (ideal 272). I have tried <span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">MAGNETIZATION 1.0, <span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">MULLIKEN_CHARGES, <span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">ENFORCE_OCCUPATION, and U = 2.0, but none removes the warning cleanly.</li><li style="margin-top: 6px;"><span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">GEO_OPT never reaches <span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">GEOMETRY OPTIMIZATION COMPLETED. BFGS collapses, LBFGS reports false convergence, and CG oscillates.</li></ol><p style="margin: 16px 0px; color: rgb(15, 17, 21); font-family: quote-cjk-patch, Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif; font-size: 16px;">My question is: given this situation, what should I do next? Specifically:<ul style="margin: 16px 0px; padding-left: 18px; color: rgb(15, 17, 21); font-family: quote-cjk-patch, Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif; font-size: 16px;"><li>Is there a known working SCF/optimizer setup for DFT+U geometry optimization of transition-metal-oxide slabs with adsorbed molecules?</li><li style="margin-top: 6px;">Should I accept a looser <span style="box-sizing: border-box; font-style: normal; font-variant: normal; font-size-adjust: none; font-language-override: normal; font-kerning: auto; font-optical-sizing: auto; font-feature-settings: normal; font-variation-settings: normal; font-stretch: normal; font-size: 0.875em; line-height: 22px; font-family: Menlo, Monaco, Consolas, "Cascadia Mono", "Ubuntu Mono", "DejaVu Sans Mono", "Liberation Mono", "JetBrains Mono", "Fira Code", Cousine, "Roboto Mono", "Courier New", Courier, sans-serif, system-ui; background-color: rgb(235, 238, 242); border-radius: 6px; align-items: center; padding: 0px 5px; display: inline-flex;">MAX_FORCE (e.g. 1e-2) and treat the result only as a relative adsorption energy?</li></ul><p style="margin: 16px 0px; color: rgb(15, 17, 21); font-family: quote-cjk-patch, Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif; font-size: 16px;"> I would appreciate a concrete recommendation rather than a full diagnosis — I have spent a lot of time on parameter tuning and need to know which direction is worth pursuing.<p style="margin: 16px 0px; color: rgb(15, 17, 21); font-family: quote-cjk-patch, Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif; font-size: 16px;"> Below is my calculation input file.Thanks for your advice.<p style="margin: 16px 0px 0px; color: rgb(15, 17, 21); font-family: quote-cjk-patch, Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif; font-size: 16px;">Thank you, Mike -- 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 visit <a href="https://groups.google.com/d/msgid/cp2k/cb57f0fd-9396-498c-9251-bc035345514en%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/cb57f0fd-9396-498c-9251-bc035345514en%40googlegroups.com</a>.