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 />https://groups.google.com/g/cp2k/c/ugkJLz4PSSI/m/C-ProBR6BwAJ<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>
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