ABINIT Discussion Forums

I have carried out a highly converged primitive cell calculation (optcell 0, ionmov 2, followed by optcell 2) for a wurtzite/hex crystal. The input file is as follows (sorry for using mixed units, Bohr for acell, and Angstrom for xangst): autoparal 1 ecut 25 pawecutdg 25 optcell 2 dilatmx 1.05 ecuts...

On further inspection of the input files shared in 'Hybrids' page on website, featuring C diamond, N2, and CH calculations, I have a couple more questions: In N2 and CH calcs specifically, it's a 3 step process (1) ionmov with GGA-PBE (2) ionmov with PBE0 (3) ionmov with HSE06. Why was PBE0 used? A ...

I compiled abinit-8.10.2 with mpi and with mpi-io on one of the XSEDE clusters (comet to be specific). I used spack for compilation, and the install was in my local directory (no system wide install). The package appears to be working fine in serial mode. However, when I have a multi-dataset run (nd...

Can abinit 8.10.2 or 8.10.3 be used for hybrid functional calculations? specifically B3LYP or HSE06. I need to do a dimer calculation for two different atom types. The Hybrid page on abinit website says I can do it in two steps: (1) do a ground-state calc in GGA, (2) do a hybrid calc. For step 1, do...

I need to create a vacany in a supercell by removing one of the atoms. But that vacancy needs to be in a charged state. I know I can specify 'charge value' in the input file but that is for the whole cell in general, not specific to the vacancy. Is there a way to specify a charge for a vacancy (or e...

Eric, I have good news. I conducted a '+U' run with the U value reported in the paper and, with a few other changes in the input file (increase of ecut from 20 Ha to 25 Ha and pawecutdg from 40 Ha to 60 Ha, setting N spinat to zero), I was able to get a magnetic moment of 0.183 uB, which is between ...

Eric, I just realized I missed a line in PAW paper that mentioned that the calculations were carried out using '+U' formalism (I originally thought +U was used only to generate U fitting values but not for non-AE result validation against AE). I hope this turns out to be a key point and fixes my res...

Eric, thanks for your two responses. Between FeO, MnO, higher ecut, and turning N spinat off, I think I have a handful of direction to try. I will work on it and see if I get more updates.

I increased ngkpt to 8 8 8, nstep to 200, ecut is 20.0, pawecutdg 40.0. And used very high values for z component of Yb's spinat (from 10 to 32). And following are the results (spinat vs magnetic-moments): 1.0000000000E+01 1.75317468E+00 1.2000000000E+01 2.33364378E-06 1.4000000000E+01 5.18211156E-0...

To elaborate further, I think the randomness may have been due to using too little k-points (ngkpt 2 2 2). I ran it again with ngktp 6 6 6 and the magnetization goes even lower. The values so far are as follows: Magnetization (Bohr magneton)= 5.29398019E-08 Magnetization (Bohr magneton)= 2.28816879E...

I have done ndtset studies for both unconstrainted (spinat ranging from [0,0,1.0] going up to [0,0,12.0]) as well as constrained (magconon_lambda at 1e-5, 1e4, 1e-3, 1e-2, etc, at fixed spinat [0,0,4]). I'm unable to reach any conclusions: - I am using spinat for Yb and N like this: [0,0,value], [0,...

Thanks so much Eric for the quick responses today. I will take your advice into account.

Thanks Eric. I will take your advise to carry out further computations. In the meantime, would you be kind enough to answer my other questions in Ground State section of this forum? (especially the YbN magnetic moment one) I haven't received any answers in the past almost two weeks and I'm under a b...

Ok, after a lot of trial and error, I've been able to do a calculation that can at least give 'Total magnetization (exact up - dn)' that is not in the 1e-5 range, but higher. This is as a result of discovering two keywords magconon and magcon_lambda, which have absolutely no mention in the tutorial ...

Just to add, this is the VLab PAW RE datasets paper, which is also recommended on this forum by the ABINIT team. ( http://www.vlab.msi.umn.edu/resources/repaw/index.shtml ) So is it possible any members of the ABINIT team have already run and verified at least part of that paper, and if yes, are the...

I'm trying to reproduce the results of one REN (YbN) out of the many REN (rare-earth nitrides) that the following paper has published: Topsakal, Wentzcovich - Accurate projected augmented wave (PAW) datasets for rare-earth elements (RE = La–Lu) I'm using their PAW dataset, with GGA-PBE for Yb, while...

If we need a spin polarized system, do we have to carry out convergence-studies/relaxation in spin polarized configuration as well? or does it suffice to do convergence/relaxation in non-spin polarized and only use spin polarized for main calculation and post-processing calculations (e.g., BS, DoS, ...

Well I generated DoS with dosdeltae of 0.001 Ha and it was a bit of an improvement but not too much. I ran with 0.004 Ha and the plot looks like this: noisydos2.png The noise is much reduced but the result is not what I'm looking for. It looks like there are unnecessary oscillations in various regio...

I made a 2x2x2 supercell out of my system and computed the DoS, and unfortunately, I now have the opposite problem, my DoS is too high-resolution and noisy (I used prtdos 2). noisydos.png High-resolution is okay, but I don't want the noise. In general I know a supercell DoS becomes more noisy becaus...

Do we relax the toldfe value (for SCF run) when we use a supercell compared to when we use a primitive cell? E.g., if we are using toldfe of 1e-12 for a 4 atom primitive cell, and now we need to do a 2x2x2 supercell calculation (32 atoms). The system is 8 times bigger, so we can use 8e-12 instead an...

I was told it may have something to do with a not well-tested PAW dataset of the impurity (because I have difficulties only when I add the impurity). My impurity is one of rare earth elements, and I recently came across VLab PAW datasets (and the paper by Topsakal) of rare earth elements, and I'm g...

Thanks so much Eric. I guess I have no more questions on this topic at the moment and I will take your advice to further my calculations.

PS: is your SCF well converged for each relaxation step? Ok I guess my understanding of optcell 0 was incorrect (especially when the log file calls it 'max grad (forces/stress)' not just 'max (forces/stress)'. I guess if it's a grad (gradient) then it makes more sense to me. As for your question, t...

The advise to first relax the internal coordinates and then relax the cell is because in many systems doing so will help the algo to converge the relaxation by reducing the number of degrees of freedom. Starting the cell relaxation after will be less far from the equilibrium than from scratch, thou...

Dear fhssn1, Your plot looks good to me, what do think is wrong actually? If you want the DOS with more unoccupied states, you have to generate a density file (or WFK) that contains enough bands, otherwise it will indeed not show them (the complain with 16 is because 16 band is not enough band to p...