Example: Broken spin-symmetry: Fe4S4

Download Fe4S4_BrokenSymm.run

#! /bin/sh

# This calculation shows a spin-flip restart feature that allows to exchange
# alpha and beta fit coefficients for selected atoms upon restart. First the
# high spin configuration with 8 more alpha-electrons than beta-electrons is
# calculated (S_z=4). Next the broken spin-symmetry configuration is calculated
# (S_z=0), using the subkey spinflip in the restart key. In this case the spin
# will be flipped for iron atoms 1 and 2. Note that the used symmetry C(2v) is
# lower than the actual symmetry T(d), such that iron atoms 1 and 2 can have a
# different spin than iron atoms 3 and 4.
#
# Please note that the syntax of the Restart key in adf2018 is different from 
# earlier versions.


"$ADFBIN/adf" <<eor
TITLE Fe4S4 High-spin configuration

ATOMS
 Fe      -0.000000000000      -1.256142548900       0.888226914500   
 Fe       0.000000000000       1.256142548900       0.888226914500   
 Fe      -1.256142548900       0.000000000000      -0.888226914500   
 Fe       1.256142548900      -0.000000000000      -0.888226914500   
  S      -1.845393493800       0.000000000000       1.304890253400   
  S       1.845393493800      -0.000000000000       1.304890253400   
  S      -0.000000000000      -1.845393493800      -1.304890253400   
  S       0.000000000000       1.845393493800      -1.304890253400   
END

Symmetry C(2v)

CHARGE 0.0 8.0

UNRESTRICTED

BASIS
type DZ
core Large
createoutput None
END

XC
GGA OPBE
END

EPRINT
 ! Omit printing of atomic population numbers since they may change per computer
 ! In real-life calculations you may want to have them
 SCF NoPOP
END

eor

mv TAPE21 Fe4S4-high-spin.t21

"$ADFBIN/adf" <<eor
TITLE Fe4S4 LOW-spin configuration

Restart 
   File Fe4S4-high-spin.t21
   ! Make sure atoms specified in the SpinFlip keyword are symmetry-equivalent
   SpinFlip 1 2
End

ATOMS
 Fe      -0.000000000000      -1.256142548900       0.888226914500   
 Fe       0.000000000000       1.256142548900       0.888226914500   
 Fe      -1.256142548900       0.000000000000      -0.888226914500   
 Fe       1.256142548900      -0.000000000000      -0.888226914500   
  S      -1.845393493800       0.000000000000       1.304890253400   
  S       1.845393493800      -0.000000000000       1.304890253400   
  S      -0.000000000000      -1.845393493800      -1.304890253400   
  S       0.000000000000       1.845393493800      -1.304890253400   
END

Symmetry C(2v)

CHARGE 0.0 0.0

UNRESTRICTED

BASIS
type DZ
core Large
createoutput None
END

XC
GGA OPBE
END

eor