May be, decreasing value of MaxForceTol helps. 2017-04-14 23:17 GMT+03:00 <zhac...@gmail.com>:
> Is there any physical reason why you think that the hexagonal symmetry > must preserve? > > Ruslan Zhachuk > > Sent from my iPhone > > On 14 апр. 2017 г., at 17:09, Sunetra Das <sunetra.das...@gmail.com> > wrote: > > Hello SIESTA users, > > I am facing a difficulty during while trying to fully relax a 32 atom > graphene like 2D system with and without a single vacancy, in the middle of > the srtucture. > A part of my input .fdf file is given below: > > > > > > > > > > > > > > > > > > > > > *DM.Tolerance 1.d-3DM.Require.Energy.Convergence > TDM.Energy.Tolerance 1.d-5 eVPAO.BasisSize DZPPAO.EnergyShift 0.3 > eVMD.TypeOfRun CGMaxSCFIterations 3000MD.NumCGsteps > 3000MD.VariableCell TMD.MaxForceTol 0.02 eV/AngMeshCutoff 300 > RyDM.MixingWeight 0.02DM.NumberPulay 3WriteCoorXmol > TWriteMullikenPop 0XC.functional GGAXC.authors > PBESolutionMethod diagonElectronicTemperature 300 K* > The lattice constant of the system, the bond length and bond angle used by > me has already been reported in a reputed journal, as a stable one. I have > not used any constraints in my structure. I have created a 4x4x1 supercell > using the reported dimensions and trying to optimize the structure with the > siesta code version 3.2-pl-5. The problem I am facing is that the optimized > structure is no longer of the symmetry I started with. The structure is no > longer a hexagonal honeycomb one anymore. > Also while using a vacancy defect in the structure the atoms are getting > asymmetrically arranged breaking any symmetry that was present there. > Now my question is, are there any more parameters that I should have > specified in the input .fdf file? > Or, will a change in the .psf file can bring about any improvement in the > optimization? > Also, if I apply some constraints like fixing the bond angles or that my > structure should relax only in a single plane, then how can I say that all > the atoms in my structure are FULLY relaxed? > > Please kindly help me in this regard. I feel like I am missing some > important parameter in my .fdf file. > Thank you. > > Regards, > Sunetra Das. > >
