<div dir="ltr">Dear Prof. Hutter,<div><br></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><br></div><p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">&GLOBAL</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">  PROJECT_NAME SS</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">  RUN_TYPE ENERGY</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">  PRINT_LEVEL MEDIUM</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">&END GLOBAL</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">&FORCE_EVAL</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">  METHOD QS</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">  &DFT</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    BASIS_SET_FILE_NAME BASIS_MOLOPT</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    POTENTIAL_FILE_NAME GTH_POTENTIALS</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    WFN_RESTART_FILE_NAME SS-RESTART.wfn</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    MULTIPLICITY 3</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    ROKS</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    &SIC</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">     SIC_METHOD EXPLICIT_ORBITALS</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">     SIC_SCALING_A 0.30</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">     SIC_SCALING_B 0.00</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    &END SIC</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    &MGRID</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      CUTOFF 400</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      REL_CUTOFF 40</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    &END MGRID</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    &XC</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      &XC_FUNCTIONAL PBE </span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      &END XC_FUNCTIONAL</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    &END XC</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    &SCF</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      MAX_SCF 20</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      EPS_SCF 1.0e-8</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      CHOLESKY INVERSE</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      SCF_GUESS RESTART</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      &OT</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">       ROTATION</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">       PRECONDITIONER FULL_KINETIC</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">       ENERGY_GAP 0.01</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">       LINESEARCH 3PNT</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      &END OT</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      &OUTER_SCF</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">       EPS_SCF 1.0e-8</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">       MAX_SCF 50</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">      &END OUTER_SCF</span></p>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">    &END SCF</span></p>
<div><span style="font-family: Menlo; font-size: 11px;">  </span><span style="font-family: Menlo; font-size: 11px;">&END DFT</span> </div><div><span style="font-family: Menlo; font-size: 11px;">  &SUBSYS</span><br></div><div><span style="font-family: Menlo; font-size: 11px;">   ....</span></div><div>   <span style="font-family: Menlo; font-size: 11px;">&END SUBSYS</span></div>
<p style="font-size: 11px; line-height: normal; font-family: Menlo;"><span style="font-variant-ligatures: no-common-ligatures">&END FORCE_EVAL</span></p><div><br></div><div><br></div><div><br></div><div>Best,</div><div>Xiaoming</div><div><br><br>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
<br>
<br>SCF_GUESS (RESTART/ATOMIC) is just for the very first guess,
<br>meaning the first SCF iteration in the first step of a MD.
<br>
<br>For initial guesses within one calculation (one MD step to the
<br>next) you have to use
<br>
<br>FORCE_EVAL / DFT / QS / EXTRAPOLATION  xxxxx
<br>
<br>In any case, if the final result depends on any of these
<br>choices, you have another problem, e.g. your convergence criteria
<br>is not strict enough, or one calculation did not converge within the 
<br>given number of steps etc.
<br>
<br>regards
<br>
<br>Juerg Hutter
<br>------------------------------<wbr>------------------------------<wbr>--
<br>Juerg Hutter                         Phone : ++41 44 635 4491
<br>Institut für Chemie C                FAX   : ++41 44 635 6838
<br>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>
<br>Winterthurerstrasse 190
<br>CH-8057 Zürich, Switzerland
<br>------------------------------<wbr>------------------------------<wbr>---
<br>
<br>-----<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>>
<br>From: Xiaoming Wang 
<br>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>
<br>Date: 10/26/2017 05:28AM
<br>Subject: [CP2K:9590] SCF_GUESS
<br>
<br>Dear all,
<br>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.
<br>Best,Xiaoming
<br>
<br>
<br>
<br>-- 
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<br></blockquote></div></div>