#!/bin/sh
# You calculate Electron Spin Resonance properties with the keywords ESR and
# QTENS. ESR is a block-type key and is used to compute the G-tensor or the
# Nuclear Magnetic Dipole Hyperfine interaction. QTENS is a simple key and
# invokes the computation of the Nuclear Electric Quadrupole Hyperfine
# interaction.
# Proper usage of the key ESR requires that you do one of the following:
# (a) A Spin-Orbit calculation, spin-restricted, with exactly one unpaired
# electron, or
# (b) A Spin-Orbit calculation, spin-unrestricted in the collinear
# approximation, or
# (c) No Spin-Orbit terms and spin-unrestricted.
# In case (a) and (b) you obtain the G-tensor. In case (b) and (c) you get the
# Magnetic Dipole Hyperfine interaction.
# Note: in case (a) the program also prints a Magnetic Dipole Hyperfine
# interaction data, but these have then been computed without the terms from the
# spin-density at the nucleus. Note: in case (b) and (c) one can have more than
# one unpaired electron. Note: in case (b) one has to use symmetry NOSYM.
# Five calculations are performed:
# - Scalar relativistic spin-restricted
# - Scalar relativistic open shell spin-restricted
# - Scalar relativistic spin-unrestricted
# - Spin-Orbit relativistic spin-restricted
# - Spin-Orbit relativistic spin-unrestricted collinear
# First a scalar relativistic spin-restricted calculation is performed. The
# TAPE21 of this calculation is saved as a fragment in the next spin-
# unrestricted calculation, using only 1 SCF iteration, which is a way to get
# the scalar relativistic spin-restricted open shell result for the magnetic
# dipole hyperfine interaction.
$ADFBIN/adf <<eor
title TiF3 scalar relativistic restricted
noprint sfo frag functions
Atoms
Ti 0 0 0
F 1.780 0 0
F -0.89 1.5415252187363007 0
F -0.89 -1.5415252187363007 0
End
Basis
Type TZ2P
Core None
End
XC
GGA Becke Perdew
End
relativistic scalar zora
eor
mv TAPE21 t21.TiF3
rm logfile
$ADFBIN/adf <<eor
title TiF3 scalar relativistic open shell restricted
noprint sfo frag functions
ESR
End
qtens
Atoms
Ti 0 0 0 f=TiF3
F 1.780 0 0 f=TiF3
F -0.89 1.5415252187363007 0 f=TiF3
F -0.89 -1.5415252187363007 0 f=TiF3
End
Fragments
TiF3 t21.TiF3
End
XC
GGA Becke Perdew
End
charge 0 1
unrestricted
scf
Iterations 0
End
relativistic scalar zora
eor
rm TAPE21 logfile
# Next a spin-unrestricted SCF calculation is performed to get the scalar
# relativistic spin-unrestricted result for the magnetic dipole hyperfine
# interaction.
$ADFBIN/adf <<eor
title TiF3 relativistic open shell unrestricted
noprint sfo frag functions
ESR
End
qtens
Atoms
Ti 0 0 0 f=TiF3
F 1.780 0 0 f=TiF3
F -0.89 1.5415252187363007 0 f=TiF3
F -0.89 -1.5415252187363007 0 f=TiF3
End
Fragments
TiF3 t21.TiF3
End
XC
GGA Becke Perdew
End
charge 0 1
unrestricted
relativistic scalar zora
eor
mv TAPE21 TiF3_scalar_zora.t21
rm logfile
# Then, for the same molecule, we compute the G-tensor in a Spin-Orbit run
# (spin-restricted).
# The here-computed and printed Dipole Hyperfine interaction misses the terms
# from the spin-density at the nucleus: compare with the outcomes from the first
# calculation.
# In each of the calculations, the QTENS key invokes the computation of the
# Electric Quadrupole Hyperfine interaction.
# 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 (and also for the Q-tensor) this plays
# a minor role, but for reasons of consistency both calculations use the same
# basis set and (absence of) frozen core.
$ADFBIN/adf <<eor
title TiF3 relativistic spinorbit open shell restricted
noprint sfo frag functions
ESR
End
qtens
Atoms
Ti 0 0 0 f=TiF3
F 1.780 0 0 f=TiF3
F -0.89 1.5415252187363007 0 f=TiF3
F -0.89 -1.5415252187363007 0 f=TiF3
End
Fragments
TiF3 t21.TiF3
End
XC
GGA Becke Perdew
End
relativistic spinorbit zora
eor
mv TAPE21 TiF3_SO_zora.t21
rm logfile
# Finally a spin-orbit coupled spin-unrestricted calculation is performed using
# the collinear approximation. Note that symmetry NOSYM is used.
$ADFBIN/adf <<eor
title TiF3 relativistic spinorbit open shell unrestricted collinear
noprint sfo frag functions
ESR
End
qtens
symmetry nosym
unrestricted
collinear
Atoms
Ti 0 0 0 f=TiF3
F 1.780 0 0 f=TiF3
F -0.89 1.5415252187363007 0 f=TiF3
F -0.89 -1.5415252187363007 0 f=TiF3
End
Fragments
TiF3 t21.TiF3
End
XC
GGA Becke Perdew
End
relativistic spinorbit zora
eor
mv TAPE21 TiF3_SO_coll.t21
rm logfile