Thanks a lot for outstanding support and help from the group. On Sun, Mar 30, 2008 at 10:22 PM, Sophia Nishad <[EMAIL PROTECTED]> wrote:
> Hi, > > I am a new user of SIESTA. I have been trying to reproduce the results for > Si as mention in Soler et. al 2002 paper, before I go for my actual > calculations. > > I have used the DZP Basis mentioned at > http://www.uam.es/departamentos/ciencias/fismateriac/siesta/ > Pseudopotential at > http://www.uam.es/departamentos/ciencias/fismateriac/siesta/ > > My calculation for 64-atoms: > 1) Lattice Constant: I changed the lattice parameter and find the energy > and plotting that I find 5.45 Ang, instead of 5.40 as reported in the > paper. Why this so different? > > 2) Bulk modulus: With B = V*Curvature = V*2c3 = 15 MPa, which is far less > than 98.6 MPa? Why? Here, c3 is defined as E =C1 + c2*V + c3*V^2, curve > fit to the E vs V curve. > > 3) Cohesive Energy: I find energy per atom 107.759eV in the bulk. Now to > calculate energy per atom I tried to use the suggestions given at > http://www.mail-archive.com/[email protected]/msg03118.html > I get -7.49eV/atom as pseudopotential calculation, and -576.38eV/atom as > ae. So, which one is the energy of the free atom. None is a good one for > comparing with the energy I got from bulk to find the cohesive energy. > > I really tried to search the archive and find solutions to these. I could > not find any explicit answers. I am not sure what I am missing. *Some > expert's simple directions can solve the problem right away*. I really > need this help. > > > Thanks in advance, > Sophia > Univ. of California - Berkeley > > Attached fdf file > > ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ > > # > ----------------------------------------------------------------------------- > # FDF for a cubic c-Si supercell with 64 atoms > # > # E. Artacho, April 1999 > # > ----------------------------------------------------------------------------- > > SystemName 64-atom Si > SystemLabel Si > > NumberOfAtoms 64 > NumberOfSpecies 1 > > %block ChemicalSpeciesLabel > 1 14 Si > %endblock ChemicalSpeciesLabel > > PAO.BasisSize DZP > PAO.EnergyShift 20 meV > > %Block PAO.Basis > Si 3 -0.46385 > n=3 0 2 E 15.42551 4.96988 > 7.00000 4.37722 > 1.00000 1.00000 > n=3 1 2 E 4.69636 3.83128 > 7.00000 4.09123 > 1.00000 1.00000 > n=3 2 1 E 11.96912 0.03131 > 4.55426 > 1.00000 > %EndBlock PAO.Basis > > > LatticeConstant 5.430 Ang > %block LatticeVectors > 2.000 0.000 0.000 > 0.000 2.000 0.000 > 0.000 0.000 2.000 > %endblock LatticeVectors > > %block kgrid_Monkhorst_Pack > 2 0 0 0.0 > 0 2 0 0.0 > 0 0 2 0.0 > %endblock kgrid_Monkhorst_Pack > > > MeshCutoff 40.0 Ry > > MaxSCFIterations 100 > DM.MixingWeight 0.3 > DM.NumberPulay 3 > DM.Tolerance 1.d-3 > DM.UseSaveDM > XC.functional LDA > XC.authors CA > > > SolutionMethod diagon > ElectronicTemperature 25 meV > > WriteForces true > WriteCoorStep true > > MD.TypeOfRun cg > MD.NumCGsteps 0 > MD.MaxCGDispl 0.1 Ang > MD.MaxForceTol 0.01 eV/Ang # earler 0.04 > SaveRho true > > AtomicCoordinatesFormat ScaledCartesian > %block AtomicCoordinatesAndAtomicSpecies > 0.00000 0.00000 0.00000 1 > 0.00000 0.50000 0.50000 1 > 0.25000 0.25000 0.75000 1 > 0.25000 0.75000 0.25000 1 > 0.50000 0.00000 0.50000 1 > 0.50000 0.50000 0.00000 1 > 0.75000 0.25000 0.25000 1 > 0.75000 0.75000 0.75000 1 > 0.00000 0.00000 1.00000 1 > 0.00000 0.50000 1.50000 1 > 0.25000 0.25000 1.75000 1 > 0.25000 0.75000 1.25000 1 > 0.50000 0.00000 1.50000 1 > 0.50000 0.50000 1.00000 1 > 0.75000 0.25000 1.25000 1 > 0.75000 0.75000 1.75000 1 > 0.00000 1.00000 0.00000 1 > 0.00000 1.50000 0.50000 1 > 0.25000 1.25000 0.75000 1 > 0.25000 1.75000 0.25000 1 > 0.50000 1.00000 0.50000 1 > 0.50000 1.50000 0.00000 1 > 0.75000 1.25000 0.25000 1 > 0.75000 1.75000 0.75000 1 > 0.00000 1.00000 1.00000 1 > 0.00000 1.50000 1.50000 1 > 0.25000 1.25000 1.75000 1 > 0.25000 1.75000 1.25000 1 > 0.50000 1.00000 1.50000 1 > 0.50000 1.50000 1.00000 1 > 0.75000 1.25000 1.25000 1 > 0.75000 1.75000 1.75000 1 > 1.00000 0.00000 0.00000 1 > 1.00000 0.50000 0.50000 1 > 1.25000 0.25000 0.75000 1 > 1.25000 0.75000 0.25000 1 > 1.50000 0.00000 0.50000 1 > 1.50000 0.50000 0.00000 1 > 1.75000 0.25000 0.25000 1 > 1.75000 0.75000 0.75000 1 > 1.00000 0.00000 1.00000 1 > 1.00000 0.50000 1.50000 1 > 1.25000 0.25000 1.75000 1 > 1.25000 0.75000 1.25000 1 > 1.50000 0.00000 1.50000 1 > 1.50000 0.50000 1.00000 1 > 1.75000 0.25000 1.25000 1 > 1.75000 0.75000 1.75000 1 > 1.00000 1.00000 0.00000 1 > 1.00000 1.50000 0.50000 1 > 1.25000 1.25000 0.75000 1 > 1.25000 1.75000 0.25000 1 > 1.50000 1.00000 0.50000 1 > 1.50000 1.50000 0.00000 1 > 1.75000 1.25000 0.25000 1 > 1.75000 1.75000 0.75000 1 > 1.00000 1.00000 1.00000 1 > 1.00000 1.50000 1.50000 1 > 1.25000 1.25000 1.75000 1 > 1.25000 1.75000 1.25000 1 > 1.50000 1.00000 1.50000 1 > 1.50000 1.50000 1.00000 1 > 1.75000 1.25000 1.25000 1 > 1.75000 1.75000 1.75000 1 > %endblock AtomicCoordinatesAndAtomicSpecies >
