ABINIT Discussion Forums

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#Definition of occupation numbers
occopt 3
tsmear  0.01

#Optimization of the lattice parameters
ixc 11
optcell 2
ionmov  3
ntime  100
dilatmx 1.1
ecutsm  0.5

#Definition of the k-point grids
kptopt 1          # Option for the automatic generation of k points, taking
                  # into account the symmetry
nshiftk 1
shiftk  0.0 0.0 0.0

ngkpt 4 4 4

nsppol 2

#Starting approximation for the unit cell
  acell   5.29  5.29  7.70

  rprim   1.0   0.0   0.0
          0.0   1.0   0.0
          0.0   0.0   1.0

#chkprim 0

#Definition of the atom types and atoms
 ntypat   2 
  znucl   22 13
  natom   2
  typat   1 2

   xred  0.0   0.0   0.0
         0.5   0.5   0.5

prtdos 1

#Definition of the planewave basis set
ecut 22.0         # Maximal kinetic energy cut-off, in Hartree

#Definition of the SCF procedure
nstep 1000          # Maximal number of SCF cycles
toldfe 1.0d-8     # Will stop when, twice in a row, the difference 
                  # between two consecutive evaluations of total energy 
                  # differ by less than toldfe (in Hartree) 
                  # This value is way too large for most realistic studies of materials

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mpiexec -np 1 abinit < TiAl.files >& log

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Choice of acell, ngfft, and ecut ===> basis sphere extends BEYOND fft box ! Recall that boxcut=Gcut(box)/Gcut(sphere) must be > 1. Action: try larger ngfft or smaller ecut. Note that ecut=effcut/boxcut*2 and effcut=0.161971