Example: Spin polarization: antiferromagnetic iron¶

#! /bin/sh

# With the UNRESTRICTED keyword we do a spin polarized calculation. Normally
# this would converge to the ferromagnetic solution.

# With the SpinFlip keyword we make sure that we start with an antiferromagnetic
# density.

# For antiferromagnetic iron we need a larger unit cell of two atoms. Since
# these atoms appear to the program as symmetry equivalent we have to specify
# them as separate types.

$ADFBIN/ams <<eor

Task SinglePoint

System
  ! The two iron atoms have different "types" to break the symmetry
  ATOMS 
    Fe.a   0.0    0.0    0.0
    Fe.b  -1.435 -1.435  1.435
  end

  Lattice
     -1.435  1.435  1.435
      1.435 -1.435  1.435
      2.87   2.87  -2.87
  End
End

Engine Band
  TITLE Beta iron

  CONVERGENCE
     CRITERION 1.0e-4
     Degenerate default
     SpinFlip 2  ! Flip (startup) spin density at second atom
  END

  Basis
     Type DZ
     Core Large
  End

  UNRESTRICTED
  
  Print AtomicChargesDetails
EndEngine
eor