$MCSCF
$MCSCF group (optional for -MCSCF-)
This group controls the MCSCF orbital optimization
step. The FULLNR method almost always exhibits good
convergence, but is more time consuming than the FOCAS
or SOSCF methods. All benefit greatly from well chosen
starting orbitals, and your having carefully read the
section on MCSCF in Chapter Four.
--- the next three choose the optimization strategy ---
- FOCAS
- = a flag to select a method, applicable only to
FORS type MCSCF functions, with first order
convergence rate. (default=.FALSE.)
- SOSCF
- = a flag selecting an approximately second order
convergence method, which is applicable only to
FORS type MCSCF functions. (default=.TRUE.)
- FULLNR
- = a flag selecting a second order method, with an
exactly computed orbital hessian. The method is
usable for FORS or non-FORS functions, although
convergence is harder with the latter. The
memory demands of this step are high, as is the
computational load. (default=.FALSE.)
--- the next apply to all three convergence methods ---
- MAXIT
- = Maximum number of iterations (default=100 for
FOCAS, 60 for SOSCF, 30 for FULLNR)
- MICIT
- = Maximum number of microiterations within a
single MCSCF iteration. (default=5 for FOCAS
or SOSCF, or 1 for FULLNR))
- ACURCY
- = the major convergence criterion, the maximum
permissible asymmetry in the Lagrangian matrix.
(default=1.0E-05)
- ENGTOL
- = a secondary convergence criterion, the run is
considered converged when the energy change is
smaller than this value. (default=1.0E-10)
- DAMP
- = damping factor, this is adjusted by the program
as necessary. (default=0.0)
- NWORD
- = The maximum memory to be used, the default is
to use all available memory. (default=0)
- CANONC
- = a flag to cause formation of the closed shell
Fock operator, and generation of canonical core
orbitals. This will order the MCC core by their
orbital energies. (default=.TRUE.)
- EKT
- = a flag to cause generation of extended Koopmans'
theorem orbitals and energies. (Default=.FALSE.)
For this option, see R.C.Morrison and G.Liu,
J.Comput.Chem., 13, 1004-1010 (1992). Note that
the process generates non-orthogonal orbitals, as
well as physically unrealistic energies for the
weakly occupied MCSCF orbitals. The method is
meant to produce a good value for the first I.P.
- NPUNCH
- = MCSCF punch option (analogous to $SCF NPUNCH)
- 0 do not punch out the final orbitals
- 1 punch out the occupied orbitals
- 2 punch out occupied and virtual orbitals
- The default is NPUNCH = 2.
- NPFLG
- = an array of debug print control. This is
analagous to the same variable in $CIINP.
Elements 1,2,3,4,6,8 make sense, the latter
controls debugging the orbital optimization.
--- the next refers to SOSCF optimizations ---
- NOFO
- = set to 1 to skip use of FOCAS for one iteration
during SOSCF. This is a testing parameter, at
present NOFO defaults to 0 to do one FOCAS iter.
--- the next three refer to FOCAS optimizations ---
- CASDII
- = threshold to start DIIS (default=0.05)
- CASHFT
- = level shift value (default=1.0)
- NRMCAS
- = renormalization flag, 1 means do Fock matrix
renormalization, 0 skips (default=1)
--- all remaining input applies only to FULLNR ---
- FORS
- = a flag to specify that the MCSCF function is of
the Full Optimized Reaction Space type, which is
sometimes known as CAS-SCF. The default is to
optimize act-act rotations. These must be
optimized if FORS was not set in $DRT, and
often convergence is better with them included
even for FORS wavefunctions. (default=.FALSE.)
- METHOD
- = DM2 selects a density driven construction of the
Newton-Raphson matrices. (default).
- = TEI selects 2e- integral driven NR construction.
- = FORMULA selects formula driven NR construction.
(the FORMULA method is now an inactive option)
See the 'further information' section for more
details concerning these methods.
- LINSER
- = a flag to activate a method similar to direct
minimization of SCF. The method is used if
the energy rises between iterations. It may in
some circumstances increase the chance of
converging excited states. (default=.FALSE.)
- FCORE
- = a flag to freeze optimization of the MCC core
orbitals, which is useful in preparation for
RUNTYP=TRANSITN jobs. Setting this flag will
automatically force CANONC false. This option
is incompatible with gradients, so can only be
used with RUNTYP=ENERGY. (default=.FALSE.)
--- the next two are seldom used ---
- NORB
- = the number of orbitals to be included in the
optimization, the default is to optimize with
respect to the entire basis. This option is
incompatible with gradients, so can only be used
with RUNTYP=ENERGY. (default=number of AOs
given in $DATA).
- NOROT
- = an array of up to 250 pairs of orbital rotations
to be omitted from the NR optimization process.
The program automatically deletes all core-core
rotations, all act-act rotations if FORS=.T.,
and all core-act and core-virt rotations if
FCORE=.T. Additional rotations are input as
I1,J1,I2,J2... to exclude rotations between
orbital I running from 1 to NORB, and J running
up to the smaller of I or NVAL in $TRANS.
--- The next 3 pertain only to METHOD=FORMULA ---
- FMLFIL
- = a flag specifying the formula tape has been
saved for reuse in this run. The default is
to regenerate this file on the 1st iteration
at the 1st geometry run. (default=.FALSE.)
- LDAR
- = length of each direct access record during the
sort of the formula tape. (default is machine
dependent)
- NDAR
- = number of direct access records. The value used
will be the larger of the program's guess of the
actual number, and the input value (default=0).
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