Have you tried including a good k-point sampling? It's the only thing that's missing, apparently - gamma-point would not be enough in this case.
Best regards, Marcos > Has anyone got any ideas why the following (Cu 001) slab flys apart after > about 22 iterations? > > Tried varying the pseudopotential, starting with the Troullier Martins > suggestion. > > I also tried translating the slab to half way along the z axis (the unit > cell is made 20 lattice parameters long along the z axis, so it's 10 > lattice parameters up). Same effect - slab sheared in two. > > If I reduce the z periodicity to approximately the same as the unit cell, > the simulation is fine, and in fact converges (forces acting on atoms > extremely small) after 1 iteration, so I'm pretty sure the FDF file > contains all the correct details. It's when the z periodicity is extended, > that's when the problems start... > > Do I need to make the unit cell variable? I'm guessing this will only > improve the x-y dimension, which I dont think is the problem... > > Thanks > > Ian > > > **************************************************************** > > > SystemName cu001 > SystemLabel cu001 > > NumberOfAtoms 60 > NumberOfSpecies 1 > > %block ChemicalSpeciesLabel > 1 29 CU # Species index, atomic number, species label > %endblock ChemicalSpeciesLabel > > PAO.BasisSize STANDARD > PAO.EnergyShift 300 meV > PAO.BasisType split > > %block Ps.lmax > CU 3 > %endblock Ps.lmax > > #AtomicCoordinatesOrigin block is in Bohr > #1 Bohr = 0.52918 angstroem > > %block AtomicCoordinatesOrigin > 1.205 1.205 1.7037 > %endblock AtomicCoordinatesOrigin > > LatticeConstant 2.55 Ang > %block LatticeVectors > 5.000 0.000 0.000 > 0.000 3.000 0.000 > 0.000 0.000 20.00 > %endblock LatticeVectors > > #MeshCutoff = equivalent plane wave cut-off for grid > > MeshCutoff 200 Ry > > MaxSCFIterations 50 > DM.MixingWeight 0.3 > DM.NumberPulay 4 > DM.Tolerance 1.d-3 > DM.UseSaveDM > > SolutionMethod diagon > ElectronicTemperature 25 meV > > MD.TypeOfRun cg > MD.NumCGsteps 40 > MD.MaxCGDispl 0.1 Ang > MD.MaxForceTol 0.04 eV/Ang > > AtomicCoordinatesFormat ScaledCartesian > %block AtomicCoordinatesAndAtomicSpecies > 0 0 0 1 > 1 0 0 1 > 2 0 0 1 > 3 0 0 1 > 4 0 0 1 > 0 1 0 1 > 1 1 0 1 > 2 1 0 1 > 3 1 0 1 > 4 1 0 1 > 0 2 0 1 > 1 2 0 1 > 2 2 0 1 > 3 2 0 1 > 4 2 0 1 > 0.5 0.5 0.7071 1 > 1.5 0.5 0.7071 1 > 2.5 0.5 0.7071 1 > 3.5 0.5 0.7071 1 > 4.5 0.5 0.7071 1 > 0.5 1.5 0.7071 1 > 1.5 1.5 0.7071 1 > 2.5 1.5 0.7071 1 > 3.5 1.5 0.7071 1 > 4.5 1.5 0.7071 1 > 0.5 2.5 0.7071 1 > 1.5 2.5 0.7071 1 > 2.5 2.5 0.7071 1 > 3.5 2.5 0.7071 1 > 4.5 2.5 0.7071 1 > 0 0 1.4142 1 > 1 0 1.4142 1 > 2 0 1.4142 1 > 3 0 1.4142 1 > 4 0 1.4142 1 > 0 1 1.4142 1 > 1 1 1.4142 1 > 2 1 1.4142 1 > 3 1 1.4142 1 > 4 1 1.4142 1 > 0 2 1.4142 1 > 1 2 1.4142 1 > 2 2 1.4142 1 > 3 2 1.4142 1 > 4 2 1.4142 1 > 0.5 0.5 2.1213 1 > 1.5 0.5 2.1213 1 > 2.5 0.5 2.1213 1 > 3.5 0.5 2.1213 1 > 4.5 0.5 2.1213 1 > 0.5 1.5 2.1213 1 > 1.5 1.5 2.1213 1 > 2.5 1.5 2.1213 1 > 3.5 1.5 2.1213 1 > 4.5 1.5 2.1213 1 > 0.5 2.5 2.1213 1 > 1.5 2.5 2.1213 1 > 2.5 2.5 2.1213 1 > 3.5 2.5 2.1213 1 > 4.5 2.5 2.1213 1 > %endblock AtomicCoordinatesAndAtomicSpecies > -- Dr. Marcos Verissimo Alves Post-Doctoral Fellow Condensed Matter and Statistical Physics Sector International Centre for Theoretical Physics Trieste, Italy -------- I have become so addicted to vi that I try to exit OpenOffice by typing :wq!
