Dear Sebastian! My calculations convverge at each MD cycle (about 300-400 SCF cycles), but max force oscillate (about 0.1-0.04 eV/anstrom) and I can not finish MD, and am already at 63 cycle and the calculation cycle is still going, although the system is quite large and contains 47 atoms. My counter question to all: does this oscillation of forces normal? I would like to strict DM.Tolerance to 0.00001 (it is VERY important to accurate calculation of forces) and to limit MD.MaxCGDispl .
Best Wishes, Maxim 2013/11/21 Sebastian Caicedo Davila <[email protected] > > Hello Diana!! > > Thanks a lot for your suggestion! I'll give it a try and maybe I'll be > bothering you again, if it is not an imposition, of course. > > Gracias de nuevo, y saludos desde tu tierra! > > Sebastian Caicedo Davila > Bionanoelectronics Research Group > School of electrical and electronics engineering > Universidad del Valle > Cali - Colombia. > > > > On Nov 21, 2013, at 11:02 AM, <[email protected]> < > [email protected]> wrote: > > Hello Sebastian, > > I have had similar problems with convergence of the scf cycle. They were > solved when I changed from Pulay mixing to Broyden mixing for the charge > density. > > Usually if something doesn't converge in 250 cycles, it probably never > will. Also you can play with the DM.Tolerance. For very difficult systems I > set it to 0.0008 and then restart from that DM file with a stringer > convergence criterion. > > Here is the settings I am using for my calculations: > > #--------------------Convergence of SCF------------------------------- > MeshCutoff 200.0 Ry # Default value PW cutoff for grid > > > MaxSCFIterations 250 # Maximum number of SCF iter > DM.NumberBroyden 3 > DM.MixingWeight 0.01 # New DM amount for next SCF cycle > DM.Tolerance 0.0001 # Tolerance in maximum difference > DM.UseSaveDM .false. # to use continuation files > > DM.NumberKick 100 > DM.KickMixingWeight 0.01 > #---------------------------------- > > Suerte! > > PS: yo tambien soy caleña! > > Diana M. Otálvaro > PhD Candidate > > Computational Material Science > MESA+ Institute of Nanotechnology > University of Twente. > Enschede, Nederland > ------------------------------ > *From:* [email protected] [[email protected]] on behalf of > Максим Арсентьев [[email protected]] > *Sent:* Wednesday, November 20, 2013 7:29 AM > *To:* [email protected] > *Subject:* Re: [SIESTA-L] Convergence problem on heterostructure. > > I forgot to tell you - besides DM.MixingWeight 0.05 I also set > PAO.EnergyShift to 65 meV as here > http://www.nature.com/nnano/journal/v7/n9/extref/nnano.2012.127-s2.txt . > > > Best wishes, > Dr. Maxim Arsent'ev > Laboratory of inorganic synthesis > Institute of Silicate Chemistry of RAS > > > 2013/11/18 Mahmoud Hammouri <[email protected]> > >> You could also try to increase the non-equilibrium contour points. >> >> Mahmoud >> >> >> On Nov 18, 2013, at 11:22, "Sebastián Cauce do Dávila" < >> [email protected]> wrote: >> >> Thank you very much for your suggestion. I will give it a try! >> >> Sebastián Caicedo Dávila >> Bionanoelectronics research group >> School of electrical and electronics engineering >> Universidad del Valle >> Cali - Colombia >> >> >> On 18/11/2013, at 11:50, Максим Арсентьев <[email protected]> wrote: >> >> I also try some siesta only six months, but for a more heterogeneous >> structure I noticed that the reduction DM.MixingWeight reduces oscillations >> in convergence, so try to play with it (decrease DM.MixingWeight). See >> http://www.nature.com/nnano/journal/v7/n9/extref/nnano.2012.127-s2.txt >> Maybe someone will tell something else. >> >> >> 2013/11/18 Sebastian Caicedo D. <[email protected]> >> >>> Dear Siesta/Transiesta users, >>> >>> I've been using the software for a couple months and made some >>> calculations of InAs and InP unit cell quite successfully. Now I intend to >>> work on transiesta calculations of a heterostructure of both these >>> materials (InAs bulk with InP barriers). As a first approach I want to >>> simulate a couple of InAs unit cells and the barriers shall be unit cells >>> of InP, just to get a qualitative idea. The electrodes .TSHS files were >>> obtained from the previous calculations of the InAs unit cell. I wanted >>> first to run a siesta calculation of the whole heterostructure, so I can >>> take a look at the eigenvalues and define a correct value for the parameter >>> TS.ComplexContour.Emin, as suggested in the manual. >>> >>> The structure has 120 atoms and I'm using LDA Pseudopotentials, obtained >>> from the siesta webpage. (In Pseudo includes semicore electrons, so we have >>> enough electrons to build a zinc-blende structure). The issue is that after >>> 1000 SCF steps, the energy doesn't converge at all. I'm doing a Gamma-point >>> calculation, but even when I make the k-grid 1x1x15 it doesn't work either. >>> >>> I used the same MeshCutoff as for the individual materials unit cell an >>> 200Ry and I increased the Energy Shift, so the calculation would be a bit >>> faster though less precise. >>> >>> I attach the Input (INPUT.fdf, STRUCTURE.fdf) and output files. >>> >>> I would really appreciate any suggestions. >>> >>> sincerely >>> >>> Sebastian Caicedo Davila >>> Bionanoelectronics Group >>> School of Electrical and Electronics Engineering >>> Universidad del Valle >>> Cali-Colombia >>> >> >> >> >> -- >> Best wishes, >> Dr. Maxim Arsent'ev >> Laboratory of inorganic synthesis >> Institute of Silicate Chemistry of RAS >> >> > > > -- > Best wishes, > Dr. Maxim Arsent'ev > Laboratory of inorganic synthesis > Institute of Silicate Chemistry of RAS > > > -- Best wishes, Dr. Maxim Arsent'ev Laboratory of inorganic synthesis Institute of Silicate Chemistry of RAS
