Dear All， I used npr algorithm for graphite cell, but cell explodes
# MgCO3 in primitive cell. SZ. Nose-Parrinello-Rahman. # SystemName MgCo3 R-3c -- SZ, 50 R -- NPR at 10 Gpa, 500K SystemLabel md_npr NumberOfSpecies 1 NumberOfAtoms 12 %block ChemicalSpeciesLabel 1 6 C %endblock ChemicalSpeciesLabel PAO.BasisSize DZP PAO.EnergyShift 65 meV # Rhombohedral primitive cell # (HEX 3-fold cell had A=4.635 and C=15.023, so alpha=48.179 degrees # and a=5.67783 Ang) LatticeConstant 1.0 Ang %block LatticeParameters 2.60164384 2.60164384 22.07568000 90.00000 90.00000 90.00000 %endblock LatticeParameters AtomicCoordinatesFormat Fractional %block AtomicCoordinatesAndAtomicSpecies 0.00000000 0.00000000 0.64583300 1 0.50000000 0.50000000 0.72916700 1 0.00000000 0.50000000 0.68750000 1 0.50000000 0.00000000 0.60416700 1 0.00000000 0.00000000 0.47916700 1 0.50000000 0.50000000 0.56250000 1 0.00000000 0.50000000 0.52083300 1 0.50000000 0.00000000 0.43750000 1 0.00000000 0.00000000 0.31250000 1 0.50000000 0.50000000 0.39583300 1 0.00000000 0.50000000 0.35416700 1 0.50000000 0.00000000 0.27083300 1 %endblock AtomicCoordinatesAndAtomicSpecies #%block GeometryConstraints # stress 3 4 5 # position 12 0.0 0.0 1.0 #%endblock GeometryConstraints MeshCutoff 200 Ry DM.NumberBroyden 4 DM.UseSaveDM T DM.MixingWeight 0.05 DM.Tolerance 1.d-4 DM.NumberPulay 8 MaxSCFIterations 400 WriteCoorStep .true. WriteForces .true. WriteMDHistory .true. WriteCoorXmol yes UseSaveData .true. SaveRho .true. # MD.UseSaveXV T MD.TypeOfRun NoseParrinelloRahman MD.Target-pressure 0.000101325 GPa MD.Target-temperature 1023 K #as in Lammps paper MD.Initial-temperature 1023 K #as in Lammps paper MD.Initial.Time.Step 1 MD.Final.Time.Step 10000 MD.Length.Time.Step 0.3 fs ============================================================= 1) do i need to use anneal to avoid exploding 2) does the gamma point not enough, or cell too small 3) what about pressure - should i use 1 atm pressure for the object heating to some temperature? which pressure should I use for the slab? -- Best wishes, Maxim Arsent'ev, Ph.D. (Chemistry) Laboratory of research of nanostructures Institute of Silicate Chemistry of RAS
-- SIESTA is supported by the Spanish Research Agency (AEI) and by the European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
