$MOROKM
$MOROKM group (relevant for RUNTYP=MOROKUMA)
This group controls how the supermolecule input in the
$DATA group is divided into two or more monomers. Both
the supermolecule and its constituent monomers must be
well described by RHF wavefunctions.
- MOROKM
- = a flag to request Morokuma-Kitaura decomposition.
(default is .TRUE.)
- RVS
- = a flag to request "reduced variation space"
decomposition. This differs from the Morokuma
option, and one or the other or both may be
requested in the same run. (default is .FALSE.)
- BSSE
- = a flag to request basis set superposition error
be computed. You must ensure that CTPSPL is
selected. This option applies only to MOROKM
decompositions, as a basis superposition error is
automatically generated by the RVS scheme. This
is not the full Boys counterpoise correction, as
explained in the reference. (default is .FALSE.)
- IATM
- = An array giving the number of atoms in each of
the monomer. Up to ten monomers may be defined.
Your input in $DATA must have all the atoms in
the first monomer defined before the atoms in the
second monomer, before the third monomer... The
number of atoms belonging to the final monomer
can be omitted. There is no sensible default for
IATM, so don't omit it from your input.
- ICHM
- = An array giving the charges of the each monomer.
The charge of the final monomer may be omitted,
as it is fixed by ICH in $CONTRL, which is the
total charge of the supermolecule. The default
is neutral monomers, ICHM(1)=0,0,0,...
- EQUM
- = a flag to indicate all monomers are equivalent
by symmetry (in addition to containing identical
atoms). If so, which is not often true, then only
the unique computations will be done.
(default is .FALSE.)
- CTPSPL
- = a flag to decompose the interaction energy into
charge transfer plus polarization terms. This
is most appropriate for weakly interacting
monomers. (default is .TRUE.)
- CTPLX
- = a flag to combine the CT and POL terms into a
single term. If you select this, you might want
to turn CTPSPL off to avoid the extra work that
that decomposition entails, or you can analyze
both ways in the same run (default=.FALSE.)
- RDENG
- = a flag to enable restarting, by reading the
lines containing "FINAL ENERGY" from a previous
run. These should be edited from an incomplete
log file and placed in a $ENERGY group.
(default is .FALSE.)
References:
C.Coulson in "Hydrogen Bonding", D.Hadzi, H.W.Thompson,
Eds., Pergamon Press, NY, 1957, pp 339-360.
C.Coulson Research, 10, 149-159 (1957).
K.Morokuma J.Chem.Phys. 55, 1236-44 (1971).
K.Kitaura, K.Morokuma Int.J.Quantum Chem. 10, 325 (1976).
K.Morokuma, K.Kitaura in "Chemical Applications of
Electrostatic Potentials", P.Politzer,D.G.Truhlar, Eds.
Plenum Press, NY, 1981, pp 215-242.
The method coded is the newer version described in the
latter two papers. Note that the CT term is computed
separately for each monomer, as described in the words
below equation 16 of the 1981 paper, not simultaneously.
Reduced Variational Space:
W.J.Stevens, W.H.Fink, Chem.Phys.Lett. 139, 15-22(1987).
BSSE during Morokuma decomposition:
R.Cammi, R.Bonaccorsi, J.Tomasi
Theoret.Chim.Acta 68, 271-283(1985).
The present implementation:
"Energy decomposition analysis for many-body interactions,
and application to water complexes"
W.Chen, M.S.Gordon J.Phys.Chem. 100, 14316-14328(1996)
The present implementation has some quirks:
- The initial guess of the monomer orbitals is not
controlled by $GUESS. The program first looks for a
$VEC1, $VEC2, ... group for each monomer. If they
are found, they will be MOREAD. If any of these are
missing, the guess for that monomer will be constructed
by HCORE. Check your monomer energies carefully!
- The use of symmetry is turned off internally.
- There is no direct SCF option. File ORDINT will
contain a full C1 list of integrals. File AOINTS
will contain whatever subset of these is needed for
each particular decomposition step. So extra disk
space is needed compared to RUNTYP=ENERGY.
- The option applies only to ab initio cases, and it
will run in parallel.
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