Hello everyone, I just started running SIESTA, and I am a complete beginner. As a test case, I decided to run simple single point calculation for lead using GGA-PBE. Here is the input script I was using:
#General system specifications SystemName Pb1 SystemLabel Pb1 NumberOfAtoms 1 NumberOfSpecies 1 # Species index, atomic number, species label %block ChemicalSpeciesLabel 1 82 Pb /scratch/ddangic/nc-sr-05_pbe_standard_psml//Pb.psml %endblock ChemicalSpeciesLabel #Atomic coordinates AtomicCoordinatesFormat Fractional %block AtomicCoordinatesAndAtomicSpecies 0.000000000000 0.000000000000 0.000000000000 1 %endblock AtomicCoordinatesAndAtomicSpecies #Unit cell for the calculation LatticeConstant 1 Ang %block LatticeVectors -0.000000000000 2.534635481000 2.534635481000 2.534635481000 0.000000000000 2.534635481000 2.534635481000 2.534635481000 0.000000000000 %endblock LatticeVectors %block kgrid_Monkhorst_Pack 8 0 0 0.0 0 8 0 0.0 0 0 8 0.0 %endblock kgrid_Monkhorst_Pack #Real space grid MeshCutoff 300.0 Ry # Convergence of SCF SCF.Mixer.History 5 SCF.H.Tolerance 1.0e-6 eV SCF.EDM.Tolerance 1.0e-6 eV # Basis set definition PAO.BasisSize DZP PAO.EnergyShift 2.000000e-03 Ry XC.functional GGA XC.authors PBE The pseudopotential is downloaded from the PseudoDojo website. I tried different value for k-point mesh (8^3 to 30^3), MeshCutoff (50 - 325 Ry) and PAO.EnergyShift (0.002 to 0.024 Ry) and I am consistently getting pressure to be around 450 GPa. This is unexpected since the lattice constant (as I understand SIESTA input) should be already close to the experimental one. Am I doing something obviously wrong? What could be the issue? Kind regards, Đorđe
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