Dear Francisco, it is difficult to give a useful advice on the basis of very limited information you provide, but my impression is that your problems are not obviously related with Vibra. Some questions: 1. What (magnetic) structure are you modelling? How comes you have four atoms per AFM unit cell? Can there be two? 2. Is electronic structure (and band dispersions) correct, prior to any phonons? 3. What means "incorrect phonon dispersion"? Do you have problems with crystallography / choosing the q-path, or is your calculation basically wrong? 4. With 4 atoms as you use it so far, the Gamma phonon calculation would yield 9 modes, which would map genuine zone-center and zone-boundary modes. Do they come out reasonably?
To your problem: "B asically I want to alter the band lines in input 2 so that they are equivalent to the band lines in input 1" - you have BandLinesScale pi/a in both inputs, the same lattice parameter, and the same definition of path. So if everything is correctly read, you must get the same Cartesian q-path in both cases. Either this is not so and there is something wrong with the input, or the paths are identical but your problem is elsewhere. Best regards Andrei ----- Le 29 Déc 22, à 0:40, garcia ff 000 <garcia.ff....@gmail.com> a écrit : > Dear Users, > I have appended 2 Vibra inputs below for computing the phonon dispersion for > FCC > Mn. > Input 1 works fine as it gives the expected band shapes for the dispersion > (but > the frequencies are off). The main issue with input 1 is that it is not > suitable for antiferromagnetic calculations since there is only one Mn atom in > the primitive cell. > This led me to consider input 2, which has 4 atoms in the unit cell and can be > used for antiferromagnetic calculations. The issue with input 2 is that the > bandlines yield an incorrect phonon dispersion. This is what I need your help > on. Basically I want to alter the band lines in input 2 so that they are > equivalent to the band lines in input 1. > Any assistance with this, especially from the Vibra authors, would be greatly > appreciated. > Thank you very much for your kind assistance and God Bless! > Francisco > #INPUT 1 (1 atom in the FCC primitive cell; 125 atoms in Supercell) > SystemName fccMn_1 > SystemLabel fccMn_1 > NumberOfAtoms 1 > LatticeConstant 3.47 Ang > %block LatticeVectors > 0.500000 0.500000 0.000000 > 0.500000 0.000000 0.500000 > 0.000000 0.500000 0.500000 > %endblock LatticeVectors > AtomicCoordinatesFormat Fractional > %block AtomicCoordinatesAndAtomicSpecies > 0.000000 0.000000 0.000000 1 54.938 > %endblock AtomicCoordinatesAndAtomicSpecies > SuperCell_1 2 > SuperCell_2 2 > SuperCell_3 2 > AtomicDispl 0.04 Bohr > BandLinesScale pi/a > %block BandLines > 1 0.000 0.000 0.000 \Gamma > 30 2.000 0.000 0.000 X > 30 2.000 2.000 2.000 \Gamma > 30 1.000 1.000 1.000 L > %endblock BandLines > Eigenvectors True > #INPUT 2 (4 atoms in the FCC conventional cell; 108 atoms in Supercell) > SystemName fccMn_4 > SystemLabel fccMn_4 > NumberOfAtoms 4 > LatticeConstant 3.47 Ang > %block LatticeVectors > 1.000000 0.000000 0.000000 > 0.000000 1.000000 0.000000 > 0.000000 0.000000 1.000000 > %endblock LatticeVectors > AtomicCoordinatesFormat Fractional > %block AtomicCoordinatesAndAtomicSpecies > 0.000000 0.000000 0.000000 1 54.938 > 0.500000 0.500000 0.000000 1 54.938 > 0.500000 0.000000 0.500000 1 54.938 > 0.000000 0.500000 0.500000 1 54.938 > %endblock AtomicCoordinatesAndAtomicSpecies > SuperCell_1 1 > SuperCell_2 1 > SuperCell_3 1 > AtomicDispl 0.04 Bohr > BandLinesScale pi/a > # The band lines below are incorrect. > %block BandLines > 1 0.000 0.000 0.000 \Gamma > 30 2.000 0.000 0.000 X > 30 2.000 2.000 2.000 \Gamma > 30 1.000 1.000 1.000 L > %endblock BandLines > Eigenvectors True > -- > SIESTA is supported by the Spanish Research Agency (AEI) and by the European > H2020 MaX Centre of Excellence > (https://urldefense.com/v3/__http://www.max-centre.eu/__;!!D9dNQwwGXtA!T-wl-ZvX-LX5xZC7QdfhJRIJ8Pmxo5HofWGt13XzKiGWhx9VgP3MXmjkoKcw2oYTy4STEEQIyWW5lU0aV4mzNGNhq7rtk7d9KA$ > )
-- SIESTA is supported by the Spanish Research Agency (AEI) and by the European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
