# An illustration of the fragment feature of ADF.
# A transition metal complex is built from a Nickel atom and four CO fragments.
# The outcomes allows for an analysis (of molecular orbitals and the Bonding
# energy) in terms of the fragment properties. It is a Single Point calculation.
# Geometry optimization would not have been possible in this set-up because an
# optimization requires that only single-atom fragments are used.
# The three atoms are created first: C, O, and Ni. For Carbon and Oxygen a type-
# DZ basis set is used (double-zeta) using the Basis key, while Ni gets a type-
# TZP basis (triple-zeta plus polarization).
# == CO ==
# The CO molecule, to serve as a fragment template in Ni(CO)4 , is computed from
# the atomic fragments C and O. The coordinate values (atoms) are in bohr,
# rather than in Angstrom because the unit-of-length is redefined by the key
# units with subkey length.
# The key scf is used to specify a somewhat tighter convergence criterion than
# the default, just to illustrate how to do this (normal settings are quite
$AMSBIN/dirac -n1 < $AMSRESOURCES/Dirac/Ni.2p
mv TAPE12 t12.rel
AMS_JOBNAME=Ni $AMSBIN/ams <<eor > tmp
Ni 0.0 0.0 0.0
create Ni $AMSRESOURCES/ADF/ZORA/TZP/Ni.2p
AMS_JOBNAME=CO $AMSBIN/ams <<eor
C 0 0 0
O 0 0 2.15617844
title CO (as fragment for NiCO4)
sfo eig ovl
# One needs to include the subkey SFO of the key EPRINT with arguments eig and
# ovl in order to get the SFO MO coefficients and SFO overlap matrix printed on
# standard output.
# == Main calculation ==
# Apart from the title, the input contains comment. This does not specify
# computational parameters but is only echoed in the output header, similar to
# the title. Contrary to the title, however, such comments are not preserved,
# apart from their echo in output and they are not written to adf.rkf or any
# other result file.
# The atomic coordinates (atoms) are given in bohr (Units). To supply the
# numerical values use is made of user-defined constants (define): 2.0053211 and
# 3.2501913. This is convenient and it prevents typing errors when several
# coordinate values are identical, in particular when they carry a lot of
# decimal places.
# The Atoms records contain also a specification of the fragments to which the
# respective atoms belong: four different CO fragments. No fragment is specified
# for the Ni atom, which implies that it is a fragment on its own.
# The numbers at the very left of the records (1 through 9, with (optionally) a
# period after them), have no relevance. You can set them for ease of reference
# or counting.
AMS_JOBNAME=NiCO4 $AMSBIN/ams <<eor
Ni 0.0 0.0 0.0
C 2.0053211 2.0053211 2.0053211 adf.f=CO|1
C -2.0053211 -2.0053211 2.0053211 adf.f=CO|2
C 2.0053211 -2.0053211 -2.0053211 adf.f=CO|3
C -2.0053211 2.0053211 -2.0053211 adf.f=CO|4
O 3.2501913 3.2501913 3.2501913 adf.f=CO|1
O -3.2501913 -3.2501913 3.2501913 adf.f=CO|2
O 3.2501913 -3.2501913 -3.2501913 adf.f=CO|3
O -3.2501913 3.2501913 -3.2501913 adf.f=CO|4
title Ni(CO)4, from fragments Ni and CO
sfo eig ovl