<div>Hello,</div><div>Have you tried to replicate the unit cell, say 5x5x5, and check if the SCF cycles converge with this large system ?</div><div>Regards.<br /></div><div> - Fernan<br /></div><br /><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Monday, January 30, 2023 at 12:01:51 AM UTC+1 Бранислав Миловановић wrote:<br/></div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Dear CP2K users,<div><br></div><div>I'm struggling with convergence for bulk Fe, i.e. 3x3x3 supercell containing 54 Fe atoms. I wanted to simulate adsorption of different organic molecules on Fe(100) slab later, so this is my starting point.</div><div><br></div><div>During GEO_OPT or CELL_OPT runs I sporadically encounter SCF issues like this:</div><div>...<br>    33 Broy./Diag. 0.70E+00    2.7     1.02510462     -7902.0344477276  2.42E+01<br>    34 Broy./Diag. 0.70E+00    2.7     1.02694146     -7882.2903511652  1.97E+01<br>    35 Broy./Diag. 0.70E+00    2.7     1.02572163     -7833.4164745080  4.89E+01<br>    36 Broy./Diag. 0.70E+00    2.7     1.02859994     -7878.1467068004 -4.47E+01<br>    37 Broy./Diag. 0.70E+00    2.7     1.02924599     -7812.2513589335  6.59E+01<br>...<br></div><div><br></div><div>and here is my DFT section:</div><div><br></div><div> &DFT<br>    BASIS_SET_FILE_NAME ${DIR}/BASIS_MOLOPT<br>    POTENTIAL_FILE_NAME ${DIR}/GTH_POTENTIALS<br>    UKS .TRUE.<br>    MULTIPLICITY 123<br>    RELAX_MULTIPLICITY 0.1<br>    CHARGE 0<br>    EXCITATIONS NONE<br>    PLUS_U_METHOD MULLIKEN          # LOWDIN, MULLIKEN_CHARGES<br>    &SCF<br>      MAX_SCF 300<br>      EPS_SCF 1.0E-6<br>      SCF_GUESS RESTART<br>      ADDED_MOS 200<br>      NOTCONV_STOPALL .FALSE.<br>      CHOLESKY RESTORE<br>      &DIAGONALIZATION<br>        ALGORITHM  STANDARD<br>        EPS_ADAPT 0.0                 # Default 0.0<br>        MAX_ITER 2                    # Default 2<br>      &END DIAGONALIZATION<br>      &MIXING<br>        METHOD BROYDEN_MIXING<br>        ALPHA 0.1                    # Default 0.4<br>        BETA 1.2                      # Default 0.5<br>        NBUFFER 6<br>         NMIXING 2<br>        NSKIP 0<br>      &END MIXING<br>      &SMEAR<br>        ELECTRONIC_TEMPERATURE [K] 500<br>        METHOD FERMI_DIRAC<br>      &END SMEAR<br>      &PRINT<br>        &RESTART<br>          BACKUP_COPIES 0<br>        &END RESTART<br>      &END PRINT<br>    &END SCF<br>    &MGRID<br>      NGRIDS 4<br>      CUTOFF 500<br>      REL_CUTOFF 50<br>    &END MGRID<br>    &QS<br>      METHOD GPW<br>      EPS_DEFAULT 1.0E-12           # Default 1.0E-10<br>      EXTRAPOLATION  ASPC           # Default<br>      EXTRAPOLATION_ORDER 3         # Default<br>    &END QS<br>    &XC<br>      &XC_FUNCTIONAL PBE<br>      &END XC_FUNCTIONAL<br>      &VDW_POTENTIAL<br>        POTENTIAL_TYPE  PAIR_POTENTIAL<br>        &PAIR_POTENTIAL<br>          R_CUTOFF 1.0583544171800002E+01         # Default<br>          TYPE DFTD3<br>          PARAMETER_FILE_NAME ${DIR}/dftd3.dat<br>          REFERENCE_FUNCTIONAL PBE<br>        &END PAIR_POTENTIAL<br>      &END VDW_POTENTIAL<br>#      &XC_GRID<br>#        XC_SMOOTH_RHO NN10<br>#        XC_DERIV SPLINE2_SMOOTH<br>##        USE_FINER_GRID F<br>#      &END XC_GRID<br>    &END XC<br>  &END DFT<br></div><div><br></div><div>What are your thoughts about parameters that I use? Do I set MAGNETIZATION, MULTIPLICITY and RELAX_MULTILIPLICITY correctly?</div><div><br></div><div>I followed the instructions from the previous discussions here in group and assembled the attached input file. Also, I looked for discussions regarding metallic systems including Fe such as:<br><a href="https://groups.google.com/g/cp2k/c/ugkJLz4PSSI/m/C-ProBR6BwAJ" target="_blank" rel="nofollow" data-saferedirecturl="https://www.google.com/url?hl=en&q=https://groups.google.com/g/cp2k/c/ugkJLz4PSSI/m/C-ProBR6BwAJ&source=gmail&ust=1708679388057000&usg=AOvVaw0hgONVryd_APXcnwfSLxAY">https://groups.google.com/g/cp2k/c/ugkJLz4PSSI/m/C-ProBR6BwAJ</a><br><br>I have an experience with the CP2K and molecular systems but not for solid state calculations.<br></div><div>Also, I have a couple of questions:</div><div>1) How does CP2K copes with SYMMETRY set to .TRUE. Is it better to leave system to break symmetry?</div><div>2) Is it good to use XC_SMOOTH_RHO to smooth XC grid in this case?</div><div><br></div><div>Thanks in advance,</div><div>Branislav</div><div> <br></div></blockquote></div>

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