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$DCCORR, without nuclear gradients. Dynamic and static
polarizabilities (but no hyperpolarizabilities) based on
DC-HF are available by specifying RUNTYP=TDHF (not TDHFX).
The initial guess is given by a density matrix, not
orbitals. The only available options are GUESS=HUCKEL,
HCORE, HUCSUB, DMREAD, and MOREAD (the latter means
orbitals for the entire system).
For a review paper on Divide-and-Conquer in GAMESS:
M.Kobayashi, H.Nakai
in Linear-Scaling Techniques in Computational
Chemistry and Physics: Methods and Applications
(Springer), Chap. 5 (2011)
For more information on the DC-SCF method, see
W.Yang, T.-S.Lee
J.Chem.Phys. 103, 5674-5678(1995)
T.Akama, M.Kobayashi, H.Nakai
J.Comput.Chem. 28, 2003-2012(2007)
T.Akama, A.Fujii, M.Kobayashi, H.Nakai
Mol.Phys. 105, 2799-2804(2007)
T.Akama, M.Kobayashi, H.Nakai
Int.J.Quant.Chem. 109, 2706-2713(2009)
M.Kobayashi, T.Yoshikawa, H.Nakai
Chem.Phys.Lett. 500, 172-177(2010) [open-shell]
M.Kobayashi, T.Kunisada, T.Akama, D.Sakura, H.Nakai
J.Chem.Phys. 134, 034105/1-11(2011) [gradient]
For more information on DC-MP2 and DC-CC, see
M.Kobayashi, Y.Imamura, H.Nakai
J.Chem.Phys. 127, 074103/1-7(2007)
M.Kobayashi, H.Nakai
J.Chem.Phys. 129, 044103/1-9(2008)
M.Kobayashi, H.Nakai
J.Chem.Phys. 131, 114108/1-9(2009)
M.Kobayashi, H.Nakai
Int.J.Quant.Chem. 109, 2227-2237(2009)
For more information on DC-TDHF polarizability, see
T.Touma, M.Kobayashi, H.Nakai
Chem.Phys.Lett. 485, 247-252(2010)
Of course, the trick to methods that divide up a large
problem into small ones is to control the errors that
result. A simple way to set up a DC-MP2 calculation is
with atomic partitions:
$contrl scftyp=rhf mplevl=2 runtyp=energy $end
$system mwords=25 $end
$scf dirscf=.true. $end
$dandc dcflg=.true. subtyp=atom bufrad=8.0 $end
$dccorr dodccr=.true. rbufcr=5.0 $end
$guess guess=hucsub $end (if DC-SCF is used)
This leads to as many subsystems as there are atoms, with
the buffer region around the central atom being defined by
a radius. This input recognizes that exchange effects in
Hartree-Fock are longer range than correlation, and thus
uses dual level radii. It may be reasonable to simply do a
conventional and thus fully accurate SCF computation by
DCFLG=.FALSE., obtaining only the MP2 correlation energy by
the divide and conquer method. Faster run times may result
from other partitionings, such as manually dividing a
protein into subsystems containing a single amino acid.
DCFLG = flag to activate DC-SCF calculation.
(default=.FALSE.)
Note: If you want to treat only the correlated MP2/CC
procedure in the DC manner, after a standard HF
calculation, this option may be set to .FALSE.
SUBTYP = chooses a method to construct disjoint
subsystems (central region).
= ATOM individual atom is 1 subsystem.
(default if NSUBS=0 or not given)
= MANUAL manually selects using NSUBS and LBSUBS
keywords. (default if NSUBS>=1)
= CARD reads from card. $SUBSCF is used for SCF
and $SUBCOR for MP2/CC calculation.
= AUTO constructs subsystems automatically by
dividing total system by cubic grid.
Grid size can be set by SUBLNG.
= AUTBND considers bond strength after AUTO.
NSUBS = number of subsystems when SUBTYP=MANUAL.
LBSUBS = an array assigning atoms to subsystems.
The style is the same as INDAT keyword in $FMO.
Two styles are supported (the choice is made based
on LBSUBS(1): if it is nonzero, choice (a) is
taken, otherwise LBSUBS(1) is ignored and choice
(b) is taken):
a) LBSUBS(i)=m assigns atom i is to subsystem m.
LBSUBS(i) must be given for each atom.
b) the style is
a1 a2 ... ak 0
b1 b2 ... bm 0
...
Elements a1...ak are assigned to subsystem 1,
then b1...bm are assigned to subsystem 2,etc.
An element is one of the following:
I or I -J
where I means atom I, and a pair I,-J means
the range of atoms I-J. There must be no space
after the "-"!
Example:
LBSUBS(1)=1,1,1,2,2,1 is equivalent to
LBSUBS(1)=0, 1,-3,6,0, 4,5,0
Both assign atoms 1,2,3 and 6 to subsystem 1,
and 4,5 to subsystem 2.
SUBLNG = grid length of cube used in SUBTYP=AUTO or AUTBND.
This value should be in the unit given by UNITS
keyword in $CONTRL. (default=2.0 Angstroms).
BUFTYP = chooses a method to construct buffer region.
= RADIUS selects atoms included in spheres centered
at atoms in the central region (default).
The radius is given by BUFRAD keyword for
DC-SCF and by the RBUFCR keyword in $DCCORR
for DC-MP2/CC.
= RADSUB selects subsystems containing one or more
atom(s) which is included in spheres
centered at atoms in the central region.
This selection can avoid cutting bonds
within each subsystem.
= CARD reads from $SUBSCF or $SUBCOR card.
Only available when SUBTYP=CARD.
BUFRAD = buffer radius in DC-SCF calculation. This value
should be in the units given by UNITS keyword in
$CONTRL (default=5.0 Angstroms).
FRBETA = inverse temperature parameter of Fermi function
used in DC-SCF procedure in a.u. (default=200.0)
Reducing this value may improve SCF convergence
but may obtain worse total energy.
MXITDC = maximum number of iteration cycles for determining
Fermi level (default=100). Usually, you need not
care about this keyword.
FTOL = Fermi function cutoff factor (default=15.0).
= p The value of Fermi function less than 10**(-p)
is considered as 0. The value greater than
[1 - 10**(-p)] is considered as 1.
NDCPRT = DC print-out option which is the sum of
followings (default=0).
= +1 not used (reserved).
= +2 prints density matrix ($DM section) on punch.
= +4 prints energy corresponding to each subsystem.
Gives correct energy only in HF calculation.
= +8 prints orbitals in each subsystem.
IORBD = selects molecular orbital in total system whose
electron density is to be computed.
Print format is given in $ELDENS.
= -1, -2, ... correspond to HOMO, HOMO-1, ...
= 1, 2, ... correspond to LUMO, LUMO+1, ...
= 0 no calculation (default).
In the DC-SCF procedure, the available SCF acceleration
techniques are DIIS, DAMP, EXTRAP as well as DC-DIIS and
VFON which are specific to the DC-SCF. In DC-SCF
calculation, only DIIS is used by default. DC-DIIS
(DIIDCF=.TRUE.) is not normally needed for convergence.
The following keywords control (DC-)DIIS convergence:
DIITYP = selects the error vector used in the
standard DIIS extrapolation
= FDS Pulay's modified DIIS (e=FDS-SDF). Although
this type of error vector behaves well in
standard SCF, it may not for DC-SCF.
= DELTAF Pulay's original DIIS (e[i]=F[i]-F[i-1]),
or so-called Anderson mixing (default).
DIIQTR = .TRUE. uses orthogonal basis (in entire system)
for DIIS extrapolation. Normally, this
does not make sense in DC-SCF run.
.FALSE. uses atomic basis function for DIIS
extrapolation (default).
EXTDII = energy error threshold in absolute value for
exiting DIIS (default=0.0).
PEXDII = percentage threshold of energy error change for
exiting DIIS (default=1.0). PEXDII is
preferential to EXTDII.
DIIDCF = a flag to activate DC-DIIS interpolation
(default=.FALSE.).
ETHRDC = energy error threshold for initiating DC-DIIS.
Increasing ETHRDC forces DC-DIIS on sooner
(default = 1.D-4 if DIIDCF=.TRUE.).
The following keywords control the convergence acceleration
based on the varying fractional occupation number (VFON).
The final electronic temperature is given by FRBETA.
FONTYP = selects the variation pattern of electronic
temperature (beta) in SCF iteration
= DIIER logarithmic variation with respect to DIIS
error.
= NONE no variation (default).
BETINI = initial beta value in a.u.
(default = FRBETA/4 for FONTYP=DIIER).
FONSTA = threshold to start variation of beta
(default=1.0 for FONTYP=DIIER).
FONEND = threshold to stop variation of beta
(default=1.D-4 for FONTYP=DIIER).
When FONTYP=DIIER, the beta value used in the iteration
(of which the DIIS error is DIISer) is the following:
beta = BETINI [for DIISER>FONSTA]
= FRBETA [for DIISER<=FONEND]
= FRBETA + C_FON * Log(DIISer/FONEND) [otherwise]
where (C_FON = (BETINI-FRBETA) / Log(FONSTA/FONEND)
Option for the type of nuclear gradient:
NDCGRD = selects the DC-SCF gradient implementation
= 0 use a formula proposed by Yang and Lee in 1995
= 1 use a formula proposed by Kobayashi et al. in
2011 (default)
Next are options for printing density of states (DOS).
DOSITV = Interval between plot points in Hartree. The
default is zero,meaning no DOS print-out. If
you print out DOS, DOSITV=0.05 may be sufficient.
DOSRGL = Left end of the plot range in Hartree.
(default=-2.0)
DOSRGR = Right end of the plot range in Hartree.
(default=+2.0)
BDOS = Inverse temperature parameter (beta) for
distributing states. This value should not be
given because it is set to be equivalent to FRBETA
in $DANDC by default.
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generated on 7/7/2017