ABINIT Discussion Forums

Hi,

If you want to remove all symmetry constraints in your calculation, just set nsym to 1.

Cheers
Boris

Hi

I can't think of a single calculation that did not display this warning. I never paid it any attention and think you should do the same!

Cheers
Boris

Hi The exact value of spinat doesn't really matter, if I remember correctly it just helps with the initialization but then the magnetic moments get optimized anyway. If the electronic configuration of Gd is indeed [Xe] 4f5 5d1 6s2, then as a first guess it makes sense that the magnetic moments will ...

Hi, From what I understand you're running a 84 atom molecule on 8 cpus, this is going to be hard, though I agree 5 hours is a "little" too long... One advice regarding parallelisation: never trust autoparal. It set npfft 4 although the new minimization algorithm in abinit doesn't work when...

I realized the problem was linked to fft parallelism, and arises for all fft libraries I've tried. So the work-around is to set npfft=1. I am trying to take advantage of openmp parallelism to circumvent this limitation, but that's another story... We may have a clue about what's going on here. We h...

I think the charge keyword should do the job. It will indeed charge the whole supercell at the beginning of the calculation but usually the charge ends up being localized near or on the defect

Are you sure it is linked to the FFT parallelism? Because I'm using npfft 1 and I am still having this issue.

Openmp should not be a problem if you're using the latest version of abinit with the new implementation of the lobpcg algorithm (set by default). It works fairly well with openmp.

Hi

DFPT with PAW+spin orbit is kind of tricky and is probably glitchy at this moment. It has not been extensively tested yet.

Without spin orbit, however, you should obtain the same result with DFPT as with small displacements.

Hi

I would try first to NOT calculate the d/dk. Just read the GS wavefunctions, run the DFPT and see if that works.

Also, try using a more up to date version of abinit, as there might have been a few changes in the phonon part since 8.6.3

Hi I have the exact same issue for a large 64 atom actinide supercell with spin orbit coupling. The SCF cycle slowly degrades as the dynamics goes on, except that I cannot restart the molecular dynamics due to convergence issue. I have not been able yet to identify the source of this problem but we ...

You can also read the warning message that tells you how to solve this problem.

The high cutoff is probably because of the O dataset. The one I generated with atompaw, as well as the JTH dataset, both require a 50 Ha cutoff.

Hello Eugene

Your result with the GPAW PAW dataset is very interesting. The frequencies at Gamma are all degenerated and have values of around 0,7 THz, which seems way better.

We will look into this, thanks!

Boris

Hello Eugene, 40 cm^-1 makes approximately 1.2 THz. Usually my frequencies at Gamma in the abinit output are around 0.5 or 0.6 so it's the same order of magnitude. But you should have the first three modes nearly degenerate in frequencies so my guess would be that something went probably wrong. I ha...

Hi

Just check the occupation matrices of Eu atoms at the end of your output file and you'll get your answer. It will give you the 4f electronic occupancies.

Hi everybody We've been working a lot on DFPT+PAW and we have corrected a number of things in the code, in particular issues related to symmetries. The 7.10.4 version should work well on many systems, so for those of you who have not tried it yet, I suggest you do so and let us know about the result...

Hi

I use phonopy. You create an input file with the conventional cell, and then it gets the primitive unit cell.

It works well.

Hi A few questions/comments: 1. You have 18 frequencies, have you tried to calculate the phonon frequencies with only the 3-atom primitive unit cell ? 2. Are you using PAW dataset or norm conserving pseudopotentials? 3. Are your first three frequencies zero? 4. Go in the output file, and search for ...

Hi

The calculation of elastic constants is not yet available in PAW.

Hello Uma I see what you mean. If indeed you cannot run the second dataset completely, you need to split it in more dataset. For supercells, here's what I personally do: - 1st dataset : the ground state - 2nd dataset : I displace only the first ten atoms, using rfatpol2 = 1 10 - 3rd dataset : I disp...

Hello Did your first job produce a DDB file? In the second run you specified rfatpol=20 108 so it is normal that in your second DDB (DS2_DDB), you have only the information starting from the 20nd atom. You need to merge the 2 DDB's with mrgddb, then you should have a complete DDB with all atoms. Boris

Hi

Yes it is available using LDA+U only (not GGA+U). It works just like the tutorial on the abinit website except you'll need PAW dataset instead of pseudopotentials.

Boris

Hi Chris

During a RF calculation, the atoms are not displaced.The second derivative of the total energy is calculated analytically. It's not like a frozen phonon calculation where you have to displace an atom and calculate the forces that act on each atom relative to this displacement.

Boris

thank you Boris for your reply. I tried but it does not converge Hi again It may be a parallelisation issue. How many cpus are you using for the calculation ? Thanks to the symmetries, the number of kpts has been reduced to 48. If you use more than 48 cores, abinit will switch to band parallelisati...