I was wondering how to decide whether it is converge? change the kpoint until the energy(eV) change is less than 0.01eV or...? Thanks!
-- Best Regards 邱芳瑜 Chiu Fang Yu 國立成功大學 材料科學與工程學系碩二 MOBILE：0930287221(中華) GMAIL：[email protected] <[email protected]> 2014-12-17 14:51 GMT+08:00 joyce79928cc . <[email protected]>: > > Thanks for reply. I will try to fix it! > > -- > Best Regards > > 邱芳瑜 Chiu Fang Yu > 國立成功大學 材料科學與工程學系碩二 > MOBILE：0930287221(中華) > GMAIL：[email protected] <[email protected]> > > > > 2014-12-17 14:38 GMT+08:00 <[email protected]>: >> >> Dear joyce79928: >> >> just some ideas. >> Your results may be noise due to insufficient basis and/or >> insufficient k-mesh ans/or insufficient MeshCutoff >> (probably all three). >> Does your DOS have any resemblance with what is expected for a 1-dim. >> chain? >> Does your stress definition in the GeometryConstrains block >> serve any purpose? >> There is a number of works with Siesta on Au chains around, >> maybe scroll through them first. >> Anyway, you can systematically proceed in the following way: >> >> Take just one atom along the chain step, not three >> (make the third lattice vector shorter :-). >> Fix it. >> For the k-mesh, you need just 1 point in the plane but more than 4 >> along Z. >> Run a sequence of calculations just varying the 3d lattice vector >> (chain step) - single point, no relaxation. >> Trace the total energy curve as function of chain step. >> This will give you an approximation to "true Siesta" result. >> Study how it depends on basis, k-mesh and MeshCutoff. >> Find "good" values for all three. >> Make the usual "egg box" test. >> Then hopefully your forces will be OK so that >> you can add more atoms to your unit, release them, let them relax etc. >> >> Good luck >> >> Andrei >> >> [email protected] >> >> >> > Dear: >> > >> > I want to relax the chain with Siesta. >> > but different atom position with same parameter will get different >> > structure. >> > for example, I set the distance between chain to 2.93 A and get a final >> > structure of 2.569 A between chain. >> > Then I change initial chain distance to 2.88 A and get a final structure >> > of >> > 2.758 A between chain. >> > >> > why this happened? >> > >> > Thanks for reading my mail and it is welcome to discuss with me. >> > >> > below's are my fdf input file. >> > >> > SystemName bulk_au >> > SystemLabel bulk_au >> > >> > ================================================== >> > ================================================== >> > # SPECIES AND BASIS >> > >> > # Number of species >> > NumberOfSpecies 1 >> > %block ChemicalSpeciesLabel >> > 1 79 Au >> > %endblock ChemicalSpeciesLabel >> > >> > PAO.BasisSize SZP >> > PAO.EnergyShift 0.04 Ry >> > >> > >> > # K-points >> > >> > %block kgrid_Monkhorst_Pack >> > 4 0 0 0.0 >> > 0 4 0 0.0 >> > 0 0 4 0.5 >> > %endblock kgrid_Monkhorst_Pack >> > >> > >> > # UNIT CELL AND ATOMIC POSITIONS >> > >> > # UNIT CELL >> > LatticeConstant 1.0 Ang >> > %block LatticeVectors >> > 8.81553253 0.00000000 0.00000000 >> > 4.40776625 7.63447409 0.00000000 >> > 0.00000000 0.00000000 8.79434817 >> > %endblock LatticeVectors >> > >> > # Atomic coordinates >> > NumberOfAtoms 3 >> > AtomicCoordinatesFormat ScaledCartesian >> > %block AtomicCoordinatesAndAtomicSpecies >> > 4.407766232 4.241374236 0.00000000 1 >> > 4.407766232 4.241374236 2.93144939 1 >> > 4.407766232 4.241374236 5.86289878 1 >> > %endblock AtomicCoordinatesAndAtomicSpecies >> > >> > ================================================== >> > ================================================== >> > # General variables >> > >> > ElectronicTemperature 300 K >> > MeshCutoff 200. Ry >> > xc.functional LDA # Exchange-correlation functional >> > xc.authors CA >> > SpinPolarized .false. >> > SolutionMethod Diagon >> > >> > >> > # SCF variables >> > >> > DM.MixSCF1 T >> > MaxSCFIterations 300 # Maximum number of SCF iter >> > DM.MixingWeight 0.03 # New DM amount for next SCF cycle >> > DM.Tolerance 1.d-4 # Tolerance in maximum difference >> > DM.UseSaveDM true # to use continuation files >> > DM.NumberPulay 5 >> > #Diag.ParallelOverK yes >> > >> > # MD variables >> > >> > MD.FinalTimeStep 1 >> > MD.TypeOfRun CG >> > MD.NumCGsteps 50 >> > MD.VariableCell T >> > UseSaveData T >> > >> > # Output variables >> > >> > WriteMullikenPop 1 >> > WriteBands .false. >> > SaveRho .false. >> > SaveDeltaRho .false. >> > SaveHS .false. >> > SaveElectrostaticPotential True >> > SaveTotalPotential no >> > WriteCoorXmol .true. >> > WriteMDXmol .true. >> > WriteMDhistory .false. >> > WriteEigenvalues yes >> > >> > %block GeometryConstraints >> > stress 4 5 6 >> > position 1 >> > %endblock GeometryConstraints >> > >> > >> > >> > -- >> > Best Regards >> > >> > 邱芳瑜 Chiu Fang Yu >> > 國立成功大學 材料科學與工程學系碩二 >> > MOBILE：0930287221(中華) >> > GMAIL：[email protected] <[email protected]> >> > >> >> >> >> >>
