#!/bin/sh
# For property calculations, XC potentials with asymptotically correct (-1/r)
# behavior outside the molecule, the results tend to be superior to regular LDA
# or GGA calculations. This is especially true for small molecules and for
# properties that depend heavily on the proper description of the outer region
# of the molecule. In the example, all-electron basis sets are used. This is
# mandatory for the SAOP potential.
# In the first example, excitation energies are calculated with the GRACLB
# potential. This potential requires one number as argument: the experimental
# ionization potential in atomic units. This number can be either based on an
# experimental value, or on previous GGA total energy calculations.
$ADFBIN/adf <<EOR
title CO excitations grac potential
BeckeGrid
Quality good
End
XC
Model GRACLB 0.515
End
Atoms
O 0 0 0
C 1.128205364 0 0
end
Excitations
Lowest 10
Onlysing
End
Basis
Type TZ2P
Core None
End
EOR
rm TAPE21 logfile
# The same calculation with the SAOP XC potential would differ in the XC block
# only:
$ADFBIN/adf <<EOR
title CO excitations SAOP
BeckeGrid
Quality good
End
XC
Model SAOP
End
Atoms
O 0 0 0
C 1.128205364 0 0
end
Excitations
Lowest 10
Onlysing
End
Basis
Type TZ2P
Core None
End
EOR
mv TAPE21 CO.t21
# SAOP depends on the orbitals which makes it more expensive to evaluate than
# GRAC for large molecules, but is much easier to use, since it does not require
# an ionization potential parameter as input.