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[jmlv@imr.ac.cn]

Dear everyone:
   I tried to get the equilbrium structure of TiNi unit cell (B2-structure, 2 
atoms/unit cell). But I always got a ERROR notice.

   First, I used the default of nband=1. the ERROR says:
    scfcge: ERROR -
  Potential-based CG line minimization not converged after 13 restarts.
  Action: read the eventual warnings about lack of convergence.
  Some might be relevant. Otherwise, raise nband.

   Then I followed what the code told me, changing the nband to 4, the usual 
value for metals. There is an ERROR again, saying:
    chkneu: ERROR -
  Initialization of occ, with occopt=   3
  There are not enough bands to get charge balance right
  Action: modify input file...
  (check the pseudopotential charges, the variable charge,
  and the declared number of bands, nband)

   What am I gonna do? Is there something wrong with the setting of nband? 
Any suggestion would be appreciated. Thanks in advance.

   The GGA-FHI pseudopotentials were used. The input file goes:

# Relaxation of TiNi B2 phase unit cell

#Definition of the unit cell
acell  3*5.67        # Lattice constants.
rprim  1.0 0.0 0.0   #
       0.0 1.0 0.0   #
       0.0 0.0 1.0   #

#Definition of the atom types
ntypat 2          # Type of constituent atoms.
znucl 22 28       # Atomic number of each atom. 
                         
#Definition of the atoms
natom 2           # There are two atoms.
typat 1 2         # One is Ti atom and another is Ni atom. 
xred              # Location of the atoms
   0.0  0.0  0.0  # Triplet giving the REDUCED coordinate of atom 1.
   0.5  0.5  0.5  # Triplet giving the REDUCED coordinate of atom 2.

#Definition of the planewave basis set
ecut  15.0        # Maximal kinetic energy cut-off, in Hartree

#Definition of the k-point grid
kptopt 1          # Automatic generation of k points, taking
                  # into account the symmetry
ngkpt 6 6 6       # This is a 2x2x2 grid based on the primitive vectors
nshiftk 4         # of the reciprocal space (that form a BCC lattice !),
                  # repeated four times, with different shifts:
shiftk
  0.5 0.5 0.5     # In cartesian coordinates, this grid is simple cubic, and
  0.5 0.0 0.0     # actually corresponds to the 
  0.0 0.5 0.0     # so-called 4x4x4 Monkhorst-Pack grid
  0.0 0.0 0.5

#Definition of optimization parameters
optcell    1         # Full optimization of cell geometry.
ecutsm     0.5       # Default is 0.0. When optcell/=0, it should be larger 
than zero.
strprecon  0.001     # Default is 1.0. But in this case, it is decreased.
ionmov     2         # Use the Broyden algorithm.
dilatmx    3.0       # Default is 1.0. Here it is increased to 1.1.
ntime      30        # Max. number of Broyden "time steps".
tolmxf     1.0E-5    # Stopping criterion for geometry optimization.

occopt     3      #
tsmear     0.04   #
ixc        11     #
nband      4      # Changed from 1(the default) to 4(usually for metals) 
after ABINIT's notice.

#Definition of the SCF procedure
nstep      100    # Maximal number of SCF cycles
toldfe     1.0E-6 # 
diemac     1.0E6  #

#Output control
prtwf    0        # Do not creat the HUGE wavefunction file. Default is 1.