#!/bin/sh

# For the ESR g-tensor and D-tensor (zero-field splitting, ZFS) the effect of
# spin-orbit coupling is important. For the ESR A-tensor and Q-tensor (EFG)
# spin-orbit coupling is less important.

# In this example first spin-orbit coupling is taken into account
# perturbatively. Next spin-orbit coupling is taken into account self-
# consistent, using the COLLINEAR keyword.

# Note that an all-electron calculation is carried out. This is relevant for the
# computation of the A-tensor, the nuclear magnetic dipole hyperfine
# interaction, where an accurate value of the spin-polarization density at the
# nucleus is important. For the g-tensor this plays a minor role. However, for
# the g-tensor calculation that includes spin-orbit coupling perturbatively, all
# electron basis sets are necessary.

# In the first ADF calculation the A-tensor (block key ESR) is calculated
# without the effect of spin-orbit coupling included. The zero-field splitting
# (key ZFS) is calculated by including spin-orbit coupling perturbatively.


"$ADFBIN/adf" <<eor
Atoms
  Hf  0.0 0.0 0.0
  V   0.0 0.0 2.033
End
ESR
END
Unrestricted
Symmetry NoSym
Charge 0 3
Basis
  Type TZ2P
  Core None
End
ZFS
QTENS
BeckeGrid
 Quality good
End
Relativistic Scalar ZORA
SAVE  TAPE21 TAPE10
eor
cp TAPE21 hfv.t21
cp TAPE10 hfv.t10
rm logfile


# In the next calculation the module nmr calculates the g-tensor (subkey
# GFACTORS) using spin-orbit coupling and the external magnetic field as
# perturbation.


$ADFBIN/nmr <<eor
nmr
 gfactors 
 u1k best
 out iso tens 
end
eor

rm TAPE21 TAPE10 logfile TAPE15
cp hfv.t21 TAPE21
cp hfv.t10 TAPE10


# The module cpl can calculate the A-tensor (key HYPERFINE) using spin-orbit
# coupling and the nuclear magnetic field as perturbation. Note that one needs
# to set the SCF convergence criterium to a small value.


$ADFBIN/cpl <<eor
hyperfine
 atoms 1 2 :: calculates A-tensor for atom 1 and 2, input order
 SCF Converge=1e-7
end
eor
rm TAPE21 TAPE10 logfile


# ADF can calculate the g-tensor and A-tensor (block key ESR) using only the
# nuclear or external magnetic field as perturbation, since spin-orbit coupling
# can be taken into account self-consistently. However, in this case, degenerate
# perturbation theory is used. The collinear approximation is used (and symmetry
# NOSYM) to account for spin-polarization effects.


"$ADFBIN/adf" <<eor
Atoms
  Hf  0.0 0.0 0.0
  V   0.0 0.0 2.033
End
ESR
END
QTENS
collinear
Unrestricted
Symmetry NoSym
Basis
  Type TZ2P
  Core None
End
BeckeGrid
 Quality good
End
Relativistic Spinorbit ZORA
eor