<div dir="ltr">Dear Prof. Hutter,<div> </div><div>I encountered the same problem again. I am doing simple ENERGY calculations. I have reduced the EPS_SCF to 1.0E-8, but still the total energy I obtained are different for the two cases: one is using SCF_GUESS of ATOMIC, and the other is RESTART, where the restart wave function is from a converged one of a similar structure with several atoms slightly distorted. Other features of my calculation are ROKS and SIC included. I am wondering why those two setups give such different results. The energy difference can be as large as 0.01 Ha. Following is my input:</div><div> </div>&GLOBAL PROJECT_NAME SS RUN_TYPE ENERGY PRINT_LEVEL MEDIUM &END GLOBAL &FORCE_EVAL METHOD QS &DFT BASIS_SET_FILE_NAME BASIS_MOLOPT POTENTIAL_FILE_NAME GTH_POTENTIALS WFN_RESTART_FILE_NAME SS-RESTART.wfn MULTIPLICITY 3 ROKS &SIC SIC_METHOD EXPLICIT_ORBITALS SIC_SCALING_A 0.30 SIC_SCALING_B 0.00 &END SIC &MGRID CUTOFF 400 REL_CUTOFF 40 &END MGRID &XC &XC_FUNCTIONAL PBE &END XC_FUNCTIONAL &END XC &SCF MAX_SCF 20 EPS_SCF 1.0e-8 CHOLESKY INVERSE SCF_GUESS RESTART &OT ROTATION PRECONDITIONER FULL_KINETIC ENERGY_GAP 0.01 LINESEARCH 3PNT &END OT &OUTER_SCF EPS_SCF 1.0e-8 MAX_SCF 50 &END OUTER_SCF &END SCF <div> &END DFT </div><div> &SUBSYS </div><div> ....</div><div> &END SUBSYS</div> &END FORCE_EVAL<div> </div><div> </div><div> </div><div>Best,</div><div>Xiaoming</div><div> On Friday, October 27, 2017 at 4:32:51 AM UTC-4, jgh wrote:<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;">Hi SCF_GUESS (RESTART/ATOMIC) is just for the very first guess, meaning the first SCF iteration in the first step of a MD. For initial guesses within one calculation (one MD step to the next) you have to use FORCE_EVAL / DFT / QS / EXTRAPOLATION xxxxx In any case, if the final result depends on any of these choices, you have another problem, e.g. your convergence criteria is not strict enough, or one calculation did not converge within the given number of steps etc. regards Juerg Hutter -------------------------------------------------------------- Juerg Hutter Phone : ++41 44 635 4491 Institut für Chemie C FAX : ++41 44 635 6838 Universität Zürich E-mail: <a href="javascript:" target="_blank" gdf-obfuscated-mailto="Hxq6JpwBCAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">hut...@chem.uzh.ch</a> Winterthurerstrasse 190 CH-8057 Zürich, Switzerland --------------------------------------------------------------- -----<a href="javascript:" target="_blank" gdf-obfuscated-mailto="Hxq6JpwBCAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp...@googlegroups.com</a> wrote: -----To: cp2k <<a href="javascript:" target="_blank" gdf-obfuscated-mailto="Hxq6JpwBCAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp...@googlegroups.com</a>> From: Xiaoming Wang Sent by: <a href="javascript:" target="_blank" gdf-obfuscated-mailto="Hxq6JpwBCAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp...@googlegroups.com</a> Date: 10/26/2017 05:28AM Subject: [CP2K:9590] SCF_GUESS Dear all, For BAND, OPT or MD calculations, one usually sets SCF_GUESS to RESTART, which will use the WFN of the previous step as a initial guess. This will usually accelerate the convergence of the SCF loops. However, The result is different from that with SCF_GUESS sed to ATOMIC. I am confused why the final results depend on the initial guess of the wfn. Best,Xiaoming -- 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="javascript:" target="_blank" gdf-obfuscated-mailto="Hxq6JpwBCAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp2k+uns...@googlegroups.com</a>. To post to this group, send email to <a href="javascript:" target="_blank" gdf-obfuscated-mailto="Hxq6JpwBCAAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp...@googlegroups.com</a>. Visit this group at <a href="https://groups.google.com/group/cp2k" target="_blank" rel="nofollow" onmousedown="this.href='https://groups.google.com/group/cp2k';return true;" onclick="this.href='https://groups.google.com/group/cp2k';return true;">https://groups.google.com/group/cp2k</a>. For more options, visit <a href="https://groups.google.com/d/optout" target="_blank" rel="nofollow" onmousedown="this.href='https://groups.google.com/d/optout';return true;" onclick="this.href='https://groups.google.com/d/optout';return true;">https://groups.google.com/d/optout</a>. </blockquote></div></div>