Dear Prof. <span>Thomas Kühne, </span><br /><br />Thank you very much for checking the UZH data and for running the control calculations yourself. The point that Al<br />was still treated as GPW in my GTH runs was new to me, and it is reassuring that FORCE_PAW / GAPW_XC give the same<br />~306 meV/Å.<br /><br />**Larger all-electron Al basis**<br /><br />Following your suggestion, I repeated the all-electron Al calculation on the initial structure with a larger basis.<br />Everything else was kept the same (GAPW + GAPW_ACCURATE_XCINT, POTENTIAL ALL); only the Al basis was changed from<br />pob-TZVP-rev2 to QZVPP-MOLOPT-PBE-ae (BASIS_MOLOPT_UZH). Al |ΔF| RMS (meV/Å):<br /><br />| Comparison | pob-TZVP-rev2 | QZVPP-MOLOPT-PBE-ae |<br />|---|---|---|<br />| GTH-SCAN-q3 vs all-electron Al | 306 | 259 |<br />| all-electron Al vs VASP PAW (Al_sv_GW) | 62 | 68 |<br /><br />- The larger basis changes the Al forces by about 60 meV/Å (other elements ≤ 6 meV/Å, pressure 0.08 kbar), so the<br /> pob-TZVP-rev2 reference was indeed not fully converged, as you expected.<br />- However, a difference of about 260 meV/Å between GTH-SCAN-q3 and the all-electron Al remains.<br /><br />I am not sure whether QZVPP-MOLOPT-PBE-ae is an appropriate choice here, since it was optimized for PBE and I use it<br />with r2SCAN, and I have no larger basis to check whether it is itself converged. Would you consider it suitable for<br />this test, or would you recommend another all-electron basis?<br /><br />**Semicore Al potential**<br /><br />I could not find a semicore (q11) GTH potential for Al with SCAN in the CP2K 2026.2 data directory. The only one I<br />found is GTH-MPC-PBE-q11 in MPC_POTENTIALS, which is a PBE potential and has no matching basis set, so I did not run<br />this comparison. If you know of a suitable semicore potential and basis, I would be happy to try it.<br /><br />**Zn**<br /><br />Thank you for the clarification. I will keep USE_FINER_GRID for production, and use GAPW + GAPW_ACCURATE_XCINT +<br />USE_FINER_GRID when lower Zn force noise is needed.<br /><br />I can send the new input and output files if they are useful.<br /><br />Thank you again for your time and help.<br /><br />Best regards,<br />Wei LIU<br /><br /><div class="gmail_quote"><div dir="auto" class="gmail_attr">在2026年10月13日星期二 UTC+9 17:10:31<Thomas Kühne> 写道：<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div style="line-break:after-white-space"><div>Dear Wei, </div><div><br></div><div>GAPW with accurate XC integration and USE_FINER_GRID seems to resolve the Zn grid problem, </div><div>but so far not the Al discrepancy. A smoother Zn potential or basis might reduce the integration cost, </div><div>but your tests do not establish that it would remove the grid sensitivity.</div><div><br></div><div>I found no evidence of corruption in the UZH data integration. The relevant entries are numerically </div><div>unchanged, and the Al potential matches the original SCAN file.</div><div><br></div><div>One important detail in your output is that Al is still treated as GPW because its basis is entirely soft </div><div><div>under the chosen decomposition settings. O and Zn receive the atom-centered GAPW treatment.</div><div><div>FORCE_PAW T enables the one-center treatment but does not itself guarantee a nonzero hard-soft </div><div>density difference. The split depends on EPSFIT and HARD_EXP_RADIUS.</div></div><div><br></div><div>I have completed control calculations for the initial structure with the same geometry, basis sets and </div><div>pseudopotentials, with GAPW_ACCURATE_XCINT T enabled in all runs. Relative to your GAPW </div><div>baseline, adding FORCE_PAW T or using GAPW_XC with FORCE_PAW T changes the Al forces by </div><div>less than 1 meV/Å. The difference from your all-electron result remains approximately 306 meV/Å.</div></div><div><br></div><div>Finally, Al GTH-SCAN-q3 contains only three explicit valence electrons. Using it with GAPW does not </div><div>restore the frozen core! An appropriate semicore potential could provide another diagnostic comparison. </div><div>Checking the basis-set convergence of your existing all-electron Al calculation would also be useful. </div><div>Checking the basis-set convergence of your all-electron Al reference would also be useful. In our own </div><div>tests, QZVPP-quality basis sets have sometimes been necessary for reliable all-electron results. </div><div>Comparing the present pob-TZVP-rev2 basis with a suitable QZVPP-quality basis would therefore be </div><div>worthwhile. However, Al potential transferability remains a plausible explanation. </div><div><br></div><div>Greetings,</div><div>Thomas</div><div><br><blockquote type="cite"></blockquote></div></div><div style="line-break:after-white-space"><div><blockquote type="cite"><div>Am 13.10.2026 um 04:33 schrieb liu wei <<a href data-email-masked rel="nofollow">whispe...@gmail.com</a>>:</div><br></blockquote></div></div><div style="line-break:after-white-space"><div><blockquote type="cite"><div><div>Dear Prof. <span>Jürg Hutter</span>, </div><div><br></div>Thank you very much for your quick and helpful reply. I ran the tests you suggested; the inputs, outputs and an<br>updated analysis script are in the attached cp2k_GTH-SCAN_report_v2.zip (new section A3 and an extended B1 in the README).<br>Please correct me if I have misread anything.<br><br>**1. Al: MOLOPT-SR basis**<br><br>I kept everything else fixed (GAPW + GAPW_ACCURATE_XCINT, all other elements TZV2P-MOLOPT-SCAN / GTH-SCAN) and changed<br>only the Al kind, on the original structure and the three MD frames. Al |ΔF| RMS against the all-electron Al<br>(meV/Å):<br><br>| Al basis + potential | initial | Al4 | Al5 | Al6 |<br>|---|---|---|---|---|<br>| TZV2P-MOLOPT-SCAN-GTH-q3 + GTH-SCAN-q3 (before) | 306 | 466 | 351 | 333 |<br>| DZVP-MOLOPT-SR-GTH-q3 + GTH-SCAN-q3 | 275 | 410 | 307 | 281 |<br>| TZV2P-MOLOPT-SR-GTH-q3 (BASIS_MOLOPT_UCL) + GTH-SCAN-q3 | 314 | 487 | 368 | 350 |<br>| DZVP-MOLOPT-SR-GTH-q3 + GTH-PBE-q3 | 172 | 245 | 187 | 181 |<br><br>- With the SR basis the Al difference changes only a little (about −10 % with DZVP-SR, no change with TZV2P-SR), so it<br> does not seem to come from the SCAN basis.<br>- Surprisingly to me, switching only the potential from GTH-SCAN-q3 to GTH-PBE-q3 removes about half of the difference,<br> in the direction of the all-electron result, although the two parameter sets differ by less than 1 %. The trend on<br> the Al–O pairs and on the relative energies of the Al4/5/6 frames is reduced in the same way, but not removed<br> (about 180 meV/Å remains).<br><br>So the Al forces seem to be very sensitive to the potential parameters. Would you expect this for GTH-SCAN-q3, and<br>would you recommend a different approach for Al in oxides with r2SCAN, for example a potential with 2s2p in the<br>valence (I could not find one for SCAN in POTENTIAL_UZH), or simply the all-electron Al with GAPW?<br><br>**2/3. Zn grid sensitivity**<br><br>Following your suggestion, I added GAPW, GAPW_ACCURATE_XCINT and USE_FINER_GRID step by step (1100 Ry, 302 atoms,<br>4 rigid shifts). Zn force spread, |ΔF| RMS (meV/Å):<br><br>| Setting | Zn spread |<br>|---|---|<br>| GPW | ~390 |<br>| GAPW + GAPW_ACCURATE_XCINT | 37 |<br>| GPW + USE_FINER_GRID | 28–32 |<br>| GAPW + GAPW_ACCURATE_XCINT + USE_FINER_GRID | 0.7–0.8 |<br><br>- The full combination works very well: the Zn noise drops below 1 meV/Å. Thank you for this.<br>- I also changed only the Zn basis to TZVP-MOLOPT-SR-GTH and the potential to GTH-PBE-q12; the noise stayed at<br> ~390 meV/Å, so with these choices it seems to come from r2SCAN on the grid rather than from the SCAN basis or potential.<br><br>May I ask one more question on this? Would it be possible, or sensible at all, to reduce this grid sensitivity on the<br>side of the potential or the basis set, for example a Zn potential/basis built to be smoother on the grid for<br>meta-GGAs? Since the SR basis and the GTH-PBE potential did not change it, I do not know whether this is something the<br>potential or basis can address.<br><br>Thank you again for your time and help.<br><br>Best regards,<br>Wei LIU<br><br><br><div class="gmail_quote"><div dir="auto" class="gmail_attr">在2026年10月12日星期一 UTC+9 22:23:26<Jürg Hutter> 写道：<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>1) You can try the Al (sr) basis from BASIS_MOLOPT. This text would give a hint if the UZH SCAN basis for Al is in some <br> way corrupted. The SCAN/Hybrid basis sets are less texted than the PBE ones. <br>2/3) r2SCAN needs higher cutoffs than PBE. If the force wiggles are too large you can try GAPW and accurate_intrgration and <br> finer_grid (in that order, accumulative) <br> <br>regards <br>JH <br> <br>________________________________________ <br>From: <a rel="nofollow">cp...@googlegroups.com</a> <<a rel="nofollow">cp...@googlegroups.com</a>> on behalf of liu wei <<a rel="nofollow">whispe...@gmail.com</a>> <br>Sent: Monday, October 12, 2026 2:15 PM <br>To: cp2k <br>Subject: [CP2K:22433] Question about Al (GTH-SCAN-q3) forces with r2SCAN compared with all-electron / PAW results <br> <br>Dear CP2K developers and users, <br> <br>I am a student working on ab initio MD of a ZnO–P2O5–Al2O3 glass (302 atoms, Γ point) with r2SCAN-D3(BJ), <br>the GTH-SCAN potentials and the MOLOPT-SCAN basis sets (CP2K 2026.2). While I was checking my forces against VASP, <br>I noticed a difference on Al that I do not understand, and I would be very grateful for your advice. I may well be <br>missing something in my setup, so please correct me if so. <br> <br>I have attached all inputs and outputs, a short analysis script (numpy only) and a README with the full tables <br>(cp2k_GTH-SCAN_report.zip). <br> <br>**1. Al forces** <br> <br>On one 302-atom structure I obtained the following force differences (|ΔF| RMS per element, meV/Å): <br> <br>| A − B | Zn | O | P | Al | <br>|---|---|---|---|---| <br>| CP2K (GPW, TZV2P-MOLOPT-SCAN, GTH-SCAN, 800 Ry, FINER) − VASP (PAW O_h/P_h/Zn/Al_sv_GW, 1300 eV) | 41 | 55 | 61 | 320 | <br>| CP2K GAPW, Al → ALL + pob-TZVP-rev2 − CP2K GAPW, Al GTH-SCAN-q3 (everything else identical) | 3 | 40 | 11 | 306 | <br>| CP2K GAPW with all-electron Al − VASP Al_sv_GW | 58 | 39 | 61 | 62 | <br> <br>- For Zn, O and P the two codes agree to about 40–60 meV/Å, and the pressure agrees to within 1 kbar, but for Al the <br> difference is about 300 meV/Å. <br>- When I replaced only the Al GTH-SCAN-q3 by an all-electron Al in GAPW, most of this difference (about 94 %) <br> disappeared in my test. <br>- I tried to check a few other possible reasons: USE_FINER_GRID, GPW vs GAPW (0.6 meV/Å <br> on Al), and the frozen 2s2p core on the VASP side (Al vs Al_sv_GW changes the Al forces by 69 meV/Å, in the other <br> direction). None of them seemed to explain it, but I am not sure whether I checked them in the right way. <br>- I also looked at three MD snapshots with 4-, 5- and 6-coordinated Al. On all 6 Al the difference seems to follow the <br> same trend: compared with the all-electron Al, GTH-SCAN-q3 appears to pull the short Al–O bonds (< 1.85 Å) in <br> and push the longer Al–O contacts (2.1 Å and beyond) out; between 1.85 and 2.1 Å the sign varies. Here I project <br> ΔF = F(all-electron) − F(GTH-SCAN-q3) on each Al–O pair as (ΔF_O − ΔF_Al)·u, with u the unit vector from Al to O. <br> A positive value means the all-electron force along the pair is more repulsive than the GTH-SCAN-q3 one (so <br> GTH-SCAN-q3 pulls the pair together), and a negative value means it is more attractive (GTH-SCAN-q3 pushes the <br> pair apart). These are differences, not the total forces. For example, I get +812 meV/Å for a bond of 1.66 Å and <br> −436 meV/Å for a contact of 2.10 Å. <br>- One limitation I am aware of: the all-electron run also uses a different Al basis (pob-TZVP-rev2), so I could not <br> separate the effect of the potential from that of the basis. Changing only the MOLOPT basis (TZVP → TZV2P) moved <br> the Al forces by 87 meV/Å, so I guessed the potential plays the larger role, but I am not confident about this. <br> <br>**2. Zn (a smaller question)** <br> <br>With GPW, r2SCAN + TZVP-MOLOPT-SCAN + GTH-SCAN-q12 gave a Zn force spread of about 390 meV/Å RMS over 4 rigid shifts <br>of the same structure, while PBEsol + TZVP-MOLOPT-SR + GTH-PBE-q12 changed by only about 2 meV/Å when the FFT grid <br>changed (1100 vs 1350 Ry). USE_FINER_GRID reduced the r2SCAN spread to about 30 meV/Å, which works well for me. <br>I did not separate the effects of the functional, the basis and the potential, so I am not sure where this comes from. <br> <br>**My questions** <br> <br>1. Could you help me understand what might cause the Al difference? Is it something one would expect with <br> GTH-SCAN-q3 (for example, because it was fitted for SCAN rather than r2SCAN), or is there likely a problem in my <br> setup or in the way I compared the results? <br>2. For Al in oxides with SCAN/r2SCAN, would you recommend a different potential or basis (for example, one with <br> 2s2p in the valence), or another way to check this more carefully? <br>3. For Zn with r2SCAN, is this grid sensitivity expected, and is there anything you would recommend besides <br> USE_FINER_GRID? <br> <br>I would be happy to run any additional tests you suggest. Thank you very much for your time and for developing <br>CP2K. <br> <br>Best regards, <br>Wei LIU <br> <br> <br>-- <br>You received this message because you are subscribed to the Google Groups "cp2k" group. <br>To unsubscribe from this group and stop receiving emails from it, send an email to <a rel="nofollow">cp2k+uns...@googlegroups.com</a><mailto:<a rel="nofollow">cp2k+uns...@googlegroups.com</a>>. <br>To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/189080b0-6d63-4515-9a04-191b65347daan%40googlegroups.com" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=zh-CN&q=https://groups.google.com/d/msgid/cp2k/189080b0-6d63-4515-9a04-191b65347daan%2540googlegroups.com&source=gmail&ust=1791974376174000&usg=AOvVaw1OL9rV8x_eHT3-CT23qQaa">https://groups.google.com/d/msgid/cp2k/189080b0-6d63-4515-9a04-191b65347daan%40googlegroups.com</a><<a href="https://groups.google.com/d/msgid/cp2k/189080b0-6d63-4515-9a04-191b65347daan%40googlegroups.com?utm_medium=email&utm_source=footer" rel="nofollow" target="_blank" data-saferedirecturl="https://www.google.com/url?hl=zh-CN&q=https://groups.google.com/d/msgid/cp2k/189080b0-6d63-4515-9a04-191b65347daan%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1791974376174000&usg=AOvVaw1EXi1sEjz-sb8hRNjyY8vZ">https://groups.google.com/d/msgid/cp2k/189080b0-6d63-4515-9a04-191b65347daan%40googlegroups.com?utm_medium=email&utm_source=footer</a>>. <br></blockquote></div><div><br></div> -- <br> You received this message because you are subscribed to the Google Groups "cp2k" group.<br></div></blockquote></div></div><div style="line-break:after-white-space"><div><blockquote type="cite"><div> 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>.<br> To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/f6b35e26-6305-4de1-abb2-c135735ab583n%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/f6b35e26-6305-4de1-abb2-c135735ab583n%2540googlegroups.com?utm_medium%3Demail%26utm_source%3Dfooter&source=gmail&ust=1791974376174000&usg=AOvVaw1THyfB6RekBpfhdJr9sks8">https://groups.google.com/d/msgid/cp2k/f6b35e26-6305-4de1-abb2-c135735ab583n%40googlegroups.com</a>.<br> <span><cp2k_GTH-SCAN_report_v2.zip></span></div></blockquote></div><br></div></blockquote></div> <p></p> -- <br /> You received this message because you are subscribed to the Google Groups "cp2k" group.<br /> 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>.<br /> To view this discussion visit <a href="https://groups.google.com/d/msgid/cp2k/86b7344d-bced-4a03-8513-2cd6eee347e0n%40googlegroups.com?utm_medium=email&utm_source=footer">https://groups.google.com/d/msgid/cp2k/86b7344d-bced-4a03-8513-2cd6eee347e0n%40googlegroups.com</a>.<br />