I have not done any calculations with Pd, but I would assume your mixing weight and NumPulay are ok. Can you maybe increase your MeshCutoff to say 400 or 450 Ry. and see what happens. If this helps your convergence, it may be beneficial to reoptimize your lattice constant since you are working with a small unit cell.
Daniel J. Backlund Texas Tech University - Physics [email protected] ________________________________________ From: L.Yue [[email protected]] Sent: Saturday, November 21, 2009 5:42 PM To: [email protected] Subject: [SIESTA-L] It's hard to get convergence Hello! Siesta users: I'm simulating the Pd(001) surface system with 23 layers. A convergence is hard to get: Ddmax stays at 0.0002. I think DM.MixingWeight (0.001) and DM.MixingWeight (8) is enough small/big. Does anybody has an advice? The convergence of 15-layer system is no problem. best regards, Lun ###### Pd(001)_surface_23.fdf SystemName fcc Pd LDA # Descriptive name of the system SystemLabel Pd # Short name for naming files # Output options LongOutput true WriteCoorXmol true SaveRho true # Species and atoms NumberOfSpecies 1 NumberOfAtoms 23 %block ChemicalSpeciesLabel 1 46 Pd %endblock ChemicalSpeciesLabel # Basis PAO.EnergyShift 50 meV PAO.BasisSize DZP LatticeConstant 3.89 Ang %block LatticeVectors 0.500 0.500 0.000 -0.500 0.500 0.000 0.000 0.000 16.000 %endblock LatticeVectors %block kgrid_Monkhorst_Pack 46 0 0 0.0 0 46 0 0.0 0 0 1 0.0 %endblock kgrid_Monkhorst_Pack %block BandLines 1 1.000 1.000 1.000 L # Begin at L 40 0.000 0.000 0.000 \Gamma # 20 points from L to gamma 45 0.000 1.000 0.000 X # 25 points from gamma to X 15 1.000 1.000 0.000 M # 10 points from W to K 45 0.000 0.000 0.000 \Gamma # 30 points from K to gamma %endblock BandLines %block ProjectedDensityOfStates -20.00 5.00 0.100 1500 eV %endblock ProjectedDensityOfStates xc.functional LDA # Exchange-correlation functional xc.authors CA # Exchange-correlation version SpinPolarized true # Logical parameters are: yes or no MeshCutoff 350. Ry # Mesh cutoff. real space mesh # SCF options MaxSCFIterations 200 # Maximum number of SCF iter DM.Tolerance 1.d-4 # Tolerance in maximum difference # between input and output DM DM.MixSCF1 true Diag.DivideAndConquer false Diag.ParallelOverK true UseSaveData true #DM.UseSaveDM true # to use continuation files DM.NumberPulay 8 DM.PulayOnFile false DM.MixingWeight 0.001 DM.NumberKick 20 DM.KickMixingWeight 0.1 SolutionMethod diagon # OrderN or Diagon OccupationFunction MP OccupationMPOrder 2 ElectronicTemperature 0.2 eV # Temp. for Fermi smearing # MD options MD.TypeOfRun cg # Type of dynamics: MD.NumCGsteps 100 # Number of CG steps for # coordinate optimization MD.MaxCGDispl 0.1 Ang # Maximum atomic displacement # in one CG step (Bohr) MD.MaxForceTol 0.003 eV/Ang # Tolerance in the maximum # atomic force (Ry/Bohr) %block GeometryConstraints position from 3 to 21 %endblock GeometryConstraints # Atomic coordinates AtomicCoordinatesFormat ScaledCartesian %block AtomicCoordinatesAndAtomicSpecies 0.000000000000 0.000000000000 11.000000000000 1 Pd 1 0.000000000000 0.500000000000 10.500000000000 1 Pd 2 0.000000000000 0.000000000000 10.000000000000 1 Pd 3 0.000000000000 0.500000000000 9.500000000000 1 Pd 4 0.000000000000 0.000000000000 9.000000000000 1 Pd 5 0.000000000000 0.500000000000 8.500000000000 1 Pd 6 0.000000000000 0.000000000000 8.000000000000 1 Pd 7 0.000000000000 0.500000000000 7.500000000000 1 Pd 8 0.000000000000 0.000000000000 7.000000000000 1 Pd 9 0.000000000000 0.500000000000 6.500000000000 1 Pd 10 0.000000000000 0.000000000000 6.000000000000 1 Pd 11 0.000000000000 0.500000000000 5.500000000000 1 Pd 12 0.000000000000 0.000000000000 5.000000000000 1 Pd 13 0.000000000000 0.500000000000 4.500000000000 1 Pd 14 0.000000000000 0.000000000000 4.000000000000 1 Pd 15 0.000000000000 0.500000000000 3.500000000000 1 Pd 16 0.000000000000 0.000000000000 3.000000000000 1 Pd 17 0.000000000000 0.500000000000 2.500000000000 1 Pd 18 0.000000000000 0.000000000000 2.000000000000 1 Pd 19 0.000000000000 0.500000000000 1.500000000000 1 Pd 20 0.000000000000 0.000000000000 1.000000000000 1 Pd 21 0.000000000000 0.500000000000 0.500000000000 1 Pd 22 0.000000000000 0.000000000000 0.000000000000 1 Pd 23 %endblock AtomicCoordinatesAndAtomicSpecies
