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4/5   4/6   4/8   4/9   4/11   4/13   4/14   4/15   4/16   4/17   4/18   4/19   4/20   4/21   4/22   4/23   4/24   4/25   4/26   4/28   4/29   4/33   4/34   4/35   4/36   4/37   4/38   4/39   4/39   4/43   4/44   4/45   4/46   4/47   4/48   4/60   4/61   4/62   4/63   4/65   4/66   4/67   4/68   4/69   4/71   4/72   4/80   4/81   4/82   4/90   4/91   4/92   4/93   4/110   4/111   4/112   4/113   4/114   4/115   4/116   4/117   4/118   4/119   4/120   4/121   4/122   4/123   4/124   4/125   4/126   4/127   4/128   4/129   4/130   4/131   4/132

Overlay 4


0 Default. This uses the Harris functional except for semi-empirical, for which the modified core Hamiltonian is diagonalized.
-1 Skip out and leave all files as left over on the rwf from whatever was done previously.
1 Read guess from the checkpoint file.
2 Guessfrom model Hamiltonian, chosen via IOp(4/11).
3 Huckel guess (only valid for NDDO-type methods).
4 Projected ZDO guess.
5 Renormalize and orthogonalize the coefficients which are on the read-write files.
6 Renormalize and orthogonalize intermediate SCF results which are on the RWF.
7 Read intermediate SCF results which are on the checkpoint file.
8 Read the generalized density specified by IOp(4/38) from the checkpoint file and generate natural orbitals from it.
9 Read the generalized density specified by IOp(4/38) from the RWF file and generate natural orbitals from it.
10-14 Generated internally and correspond to 0 and 5-8 for sparse.
16 Use the orthonormal set provided by L302 as MOs, avoiding any diagonalization.
17 Store unit matrices for a dummy guess.
18 Copy orbitals and densities that are in the chk file without checking or alteration.
100 Convert Guess=Check to Guess=Restart or to generating guess depending on what if anything is on the checkpoint file.
1000 Use the simultaneous optimization recipe: S-0.5* V.
00000 Default (1 for PBC without alter, otherwise 2).
10000 Re-use Fock matrices instead of orbitals.
20000 Re-use orbitals not Fock matrices.
100000 Read the name of a checkpoint file from the input stream and read guess MOs from it, or read an option for how to generate the guess.

Note that variable IGuess here has 4,3,2,1 corresponding to 1,2,3,4 above. IGuess values of 10-14 are generatedinternally and are the sparse versions of 0 and 5-8.


0 Default (1 except 3 for IOp(129)=1).
1 Force projected read-in guess, even when bases are identical.
2 Suppress projection.
3 Project only if basis sets are different.
00 Default orthogonalization (perform if Guess=Cards).
10 Schmidt orthogonalize guess orbitals.
20 Suppress orthogonalization.
000 Default MO checking (check if Guess=Cards or Guess=Mix).
100 Check MOs for othornormality.
200 Don’t check MOs for othornormality.
100000000 Default all 3 to on
200000000 Default all 3 to off.


0 Default (3).
1 Read in pairs of integers in free format indicating which pairs of MO’s are to be interchanged. Pairs are read until a blank card is encountered.
2 Read in a permutation of the orbitals.
3 Do not alter configuration.
10 Read alteration information from the read-write file.
100 Use alpha orbitals for guess for both alpha and beta.
1000 Biorthogonalize UHF MOs.

Note: If the configuration is altered on an open shell system, two sets of data as described above will be expected, first for alpha, second for beta.


0 Default, same as 104 except 4 for IGuess=16, and 204 if C1 symmetry.
1 Read groups of irreducible representations to combine in the SCF. These are read before any orbitals and before
alteration commands.
2 Use no symmetry in the SCF.
3 Pick up the symmetry mixing information from the alteration read-write file.
4 Use the full Abelian point group, as represented by the symmetry adapted basis functions produced by link 301. Initial guess orbital symmetries are assigned.
5 (Use symmetry in SCF if possible, but do not assign initial guess Abelian symmetries).
10 Localize all occupied orbitals together and all virtual orbitals together.
20 Localize the orbitals within the selected or defaulted symmetry.
30 Localize all occupied and virtual orbitals together.
40 Do not localize.
100 Assign orbital symmetries for printing in full symmetry.
200 Do not assign orbital symmetries in full symmetry.
1000 Force the guess orbitals to have the Abelian symmetry.
NN0000 Use localization method NN-1 (see LocMO).

This option can cause the symmetry adapted basis function common blocks to be modified.


For iterative ZDO Guess:

-1 Force old path using old Huckel.
0 Best available (8,4 in order of preference).
1 Old Huckel.
4 New Huckel.
5 Iterative extended Huckel.
6 Harris, converted to IGuess=3 and IZDO=3 here.
7 Harris with interpolated QEq atomic charges, converted to IGuess=3 IZDO=5 here.
8 Harris with new densities.
9 Iterated Harris with QEq guess, converted to IGuess=3 IZDO=7.
10 Unused.
11 NYI? Harris using charges from previous SCF, converted to IGuess=3 IZDO=9.

For unprojected single diagonalization guess:

0 Default(1 for DFTB, 2 for AM1/PM6, 3 for ab initio).
1 Use bare core matrix.
2 Dress core Hamiltonian with QEq-based density.
3 Use Harris Functional with old densities.
4 Neutral atom AM1/PMx guess.
5 Harris functional with interpolated QEq charges.
6 Harris functional with iterated charges.
7 Harris functional with iterated charges starting from QEq.
8 Use Harris Functional with new densities.
9 Harris using charges from previous SCF
000 Default, same as 2.
100 Use at least SG1 in Harris guess.
200 Use at least FineGrid in Harris guess.
300 Use at least UltraFine in Harris guess.
400 Use an unpruned (199,590) or (399,590) grid depending on the range of primitive exponents..
500 Use(399,974) and 10-12 in Harris functional.
1000 Save energy in Gen(43) for Harris functional.
MMMM00000 Use functional MMMM.


-2 No mixing.
-1 Mix HOMO and LUMO (skipping beta high-spin orbitals for GHF).
0 Default: Mix HOMO and LUMO to make complex guess for CRHF and CUHF if generating RUHF guess, otherwise do nothing.
>0 Bits request actions as follows:
     0: Mix HOMO and LUMO (skipping beta high-spin virtuals for GHF), done after complex/spin mixings.
     1: Do complex mixing, changing spin direction for GHF.
     2: Use real rather than imaginary coefficients.
     3: Flip sign of complex mixing.
     4: Read in a spin-vector and rotate to align spins in this direction instead of Z. GHF only.
     5: Read in two spin-vectors and use them for alternate orbitals.
     6: Reverse rotation direction applied to spin.
  Note that this will usually destroy both spatial and alpha/beta symmetry. The mixing is done after any alterations. Bits 1-3 are only relevant for complex wfns.


0 No.
1 Yes. For alpha orbitals, read one card with the format for the orbitals, followed by zero or more sets of IVec (I5): vector to replace. If IVec is -1, all NBasis vectors follow.(Vector(I), I=1, NBasis): vector in the specified format. Input is terminated by IVec=0. For b orbitals, the same format as for a is used. Note that if Alter is also specified, the replacements are read before the corr. alterations (thus the order is a orbitals, a alterations, b orbitals, b alterations).
2 Yes. Read using the format described in Routine RdMO2. Here a range of MOs is indicated by two integers followed by an integer giving the number of basis functions. Then a list of MO energies are given. Lastly, the MO coefficients are read in sequence. All of the reading is carried out in free format.
10 Orbitals are assumed to have mixed normalization for Cartesian d and higher functions (equivalent to having AdjMO applied to them).
100 Reorder d and f coefficients from the order used in NWChem (as of January, 2013) to the conventional order used in Gaussian.
900 Read permutation arrays for p and higher functions for use in reordering read-in MO coefficients. (NYI)


0 Use multiplicity in /Mol/.
N Use multiplicity N. Useful for generating guesses for open-shell singlets or unusual spin states involving orthogonal orbs by treating them as high-spin in the guess (which only does UHF).


0 Default (same as 3).
1 Use the basis functions as is.
2 Translate to the current atomic coordinates.
3 Translate to the current atomic coordinates, and determine an overall rotation to provide to the read-in orbitals.


0 Number of open electrons.
N N.


Number of orbitals in the CAS space.



0 Default (AM1).
3 MINDO/3.
5 AM1.
6 Unused.
7 PM3.
8 PM3 with mechanics correction.
9 Dreiding mechanics.
10 UFF mechanics.
11 AMBER mechanics.
12 MM2 mechanics.
13 MM3 mechanics.
14 Extended Huckel, Hoffmann parameters.
15 Extended Huckel, Muller parameters.
16 Extended Huckel, Initial guess parameters.
17 External program.
18 MMFF.
19 QFF.


0 Default (no Pulay, no Camp-King, 3/4 point on unless Pulay or Camp-King, use pseudo-diagonalization).
1 3/4.
2 No 3/4.
10 No Pulay (DIIS).
20 Pulay.
100 No Camp-King.
200 Camp-King.
1000 Use pseudo-diagonalization.
2000 No pseudo-diagonalization.
1 Read options from input stream.
10 Use Slater determinants.
100 Just list configurations.
1000 Use determinant basis with Sz=b/2.
10000 Write unformatted file (NDATA) of symbolic matrix elements.
100000 Write formatted file of symbolic matrix elements.


0 None.
1 1st derivatives.
2 2nd derivatives.
12 Restart 2nd derivatives.
100 Do 1st derivatives analytically if possible.


0 Default.
N N.


0 Default (don’t update).
1 Update, multiplying by S-1/2.
2 Don’t update. (For Opt=MNDOFC).
3 Update, but don’t convert from Lowdin orbitals.
10 Update second force array instead of first. (For Opt=MNDOFC).


0 Default (Same as 1).
1 Single determinant, RHF/UHF from IOp(4/5).
3 Bi-radical 1/2 CI (only for MINDO3, MNDO, AM1).
4 Closed-shell 1/3 CI (only for MINDO3, MNDO, AM1).
5 General CI, using specified orbitals.
-N General CI, with N microstates read in.


Whether to mix orbitals in generated guess density.

0 No.
-3 Yes, mix valence occupieds with 0.05 au (according to ZDO) of the HOMO and virtuals within 0.15 au.
-2 Yes, mix valence orbitals and an equal number of virtuals.
-1 Yes, mix all equally.
N       Equal occupations of the lowest N virtuals and high N occupieds.




Printing of guess.

0 No printing.
1 Print the MO coefficients.
2 Print everything.


Dump option.

0 No dump.
1 Turn on all possible printing.


0 Default (copy on disk is used).
1 Overlap assumed to be unity.
2 Copy on disk is used.


0 No.
1       Yes, reformat ZIndo integrals and wavefunction into RWF.


0 Defaults.
1 Old Si parameters.
2 Old S parameters.


Generalized density to use for natural orbitals.

0 Default (-1, current for method on chk).
N Density number N.


Angle for mixing during Guess=Mix.

0 Default (Pi/4).
N Pi/N.


00 Same as 21 for MM, 22 for everything else.
1       Consider external charges.
2 Do not consider external charges.
10 Consider self-consistent solvent charges.
20 Do not consider self-consistent solvent charges.
L405: = IDiEij: = switch for direct matrix element calculation.
0 For normal route, with all matrix elements calculated here and stored on disk. Configs printed as normal.
1 For direct route. Eij’s calculated here and stored on disk. A flag is automatically sent to L510 to tell it to compute the remaining matrix elements directly.
This type of computation can only be done in a CAS comp. Also L510 must use Lanczos.
2 Like option 1, but all configurations are printed. This will be the only way to print configs in a direct matrix element calc, since there can be many thousands in a large CAS.



Ipairs= number of GVB pairs in GVBCAS.

0       Default. No pairs, normal CAS calculation.
N There are N pairs: 2*n extra orbitals and electrons will be added into the active space later. L405 performs a CAS on the inner space, and sets up L510 to compute extra matrix elements etc. implicitly. This is a normal GVBCAS calculation.
-N There are N pairs: 2*n orbitals and electrons of the specified CAS are to be considered to be GVB type orbitals when generating configs/matrix elements. L510 will execute normally. This occupies as such space as a full CAS in this link, but is smaller subsequently. This is the GVBCAS test mode.


CI basis in CASSCF.

1 Hartree-Waller functions for singlets.
2 Hartree-Waller functions for triplets.
3 Slater determinants.
10 Write SME on disk.


Convert to sparse storage after generating guess.

-3 Save sparse storage Fock matrix for guess.
-2 Save full storage Fock matrix for guess.
-1 No, use the Lewis dot structure to generate a sparse guess directly.
0       Default (-1 if sparse is turned on).
1 Yes.


0 No.
1 Yes. Use Lewis dot structure guess density.
2 Yes. Use diagonal guess density.


Override standard values of IRadAn.


Override standard values of IRanWt.


Override standard values of IRanGd.


Flags for which terms to include in MM energy.

0 Default (111111).
1 Turn on all terms, r-1 Coulomb.
2 Turn on all terms, r-2 Coulomb.
10 Turn on non-bonded terms.
100 Turn on inversions/improper torsions.
1000 Turn on torsions.
10000 Turn on angle bending.
100000 Turn on bond stretches.


Tighten the zero thresholds as the SCF calculation proceeds.

0 Default: Yes, initial threshold 5×10-5.
1 No variable thresholds.
N Yes, initial threshold 10-N.
N<-100 Yes, initial threshold 5 x 10 N+100.


Dielectric constant to be used in MM calculations.

0 Eps = 1.0.
N Eps = N / 1000.


Whether to use QEq to assign MM charges.

0 Default (211 if UFF, 2 otherwise, 1⇒ 221).
1 Do QEq.
2 Don’t do QEq.
00 Default (20).
10 Do for atoms which were not explicitly typed.
20 Do for all atoms regardless of typing.
000 Default (200).
100 Do for atoms which have charge specified or defaulted to 0.
200 Do for all atoms regardless of initial charge.


0 Default.
N 10-N.


Whether to do a new additional guess in addition to reading orbitals from the RWF.

0 Default (2).
1 Yes if no Guess=Alter, Harris guess, and not a small geometry step.
2 Do not do the extra guess.
3 Do the extra guess and store as the initial Fock matrix.
4 Do the extra guess regardless.
5 Store the normal guess as the alternative (for SimOpt).
00 Default (10 for PBC, 20 otherwise).
10 Save the Harris guess as an initial Fock matrix.
20 Just generate orbitals from the Harris guess.


0 No
1 Yes


Irreps to keep in MCSCF CI-wavefunction.

0 All
IJKLMNOP List of up to 8 irreducible representation numbers to include.


The maximum conjugate gradient step size (MMNN).

0000 No maximum step size.
MMNN Step size of MM.NN.


Sparse SCF Parameters.

MM Maximum number of SCF DIIS cycles. (MM=00 defaults to 20 cycles, MM=01 turns DIIS off).
NN00 F(Mu,Nu) atom–atom cutoff criterion (angstroms) Mu, Nu are basis functions on the same atom.(defaults to no F(Mu,Nu) cutoff).
PP0000 F(Mu,Lambda) atom–atom cutoff criterion (angstroms) Mu, Lambda are basis functions on different atoms. (defaults to 15 angstroms).


Conjugate-Gradient Parameters.

MM Maximum number of CG cycles per SCF iteration. (defaults to 4 CG cycles).
NN00 Maximum number of purification cycles per CG iteration. (defaults to 3 cycles).
00000 Don’t use CG DIIS.
10000 Use CG DIIS.
000000 Polak-Ribiere CG minimization.
100000 Fletcher-Reeves CG minimization.
0000000 Use diagonal preconditioning in Conjugate-Gradient.
1000000 No preconditioning.


0 Default (0.025 femtosec).
N N*0.0001 femtosec.


0 Default (same as 4).
3 Read in initial Cartesian velocity.
4 Read in initial mass weighted Cartesian velocity.


0 Default (100).
N N points in trajectory.


0 Do not read isotopes.
1 Read isotopes.


1 Scale by (# fragatoms)-1.
2 Scale by 1/SQRT (# fragatoms).
N Scale by N/1000.


IDoV in Harris guess. See HarFok for details.

0 Default (2).


Compression for ONIOM.

4 Compressed Hessian over active atoms. For MM calculations on the real system, this converts a second derivative calculation to just forces, since the real system 2nd derivatives are computed during micro-iterations.
N≥4 Full storage. (default)


0 Default (First external command).
N Nthexternal command (command N in file 747).


Which ONIOM system is being done, which is sometimes needed by external procedures.

0 Default (1).
1 Real system.
2 Model system for 2-layer, middle for 3-layer.
3 Small model system for 3-layer.


Mixing of orbitals for GHF/Complex testing.

0 Default (No, unless generate guess for complex).
1 Make MO coefficients complex.
2 Don’t rotate real and imaginary components of MOs.
10 Mix alpha and beta orbitals for GHF.
100 Read in S vector to apply to FC perturbation.
200 Read in complex-style SR, SI for GHF.
0000 Default FC perturbation (1).
1000 FC with MBS core orbitals blanked.
2000 Full FC.


Functional to use in Harris guess.

0 Default: PBEPBE for HSE2PBE, HSE(H)1PBE and any functional involving the kinetic energy or Laplacian, the pure version of the functional for pure and hybrid GGAs, and SVWN3 for HF.
N Functional # (see values in 3/74).


Set flag for BD Guess=Read.

0 No.
-1 Yes.


Whether to do GHF/Complex diagonalization for Harris and Core guesses.

0 Default (1).
1 Yes.
2 No, generate UHF guess and convert.


Printing MM energy contributions and force field parameters.

0 Default (print contributions if #p).
1 Print contributions.
2 Don’t print contributions.
00 Default (20).
10 Print all terms in the force field.
20 Don’t print the force field.


0 Default, based on N Atoms but at least 5000.
0 N.


Convergence of iterative Harris guess.

0 Default (0.02).
N>0 N/10000.
N<0 10N.


Maximum number of iterations for iterated Harris:

0 Default, 20.


Control of generation QEq charges in Harris guess. See description ICntrl in GenChg.





Whether to print atomic spin vectors, etc.

0 Default (2).
1 Yes.
2 No.


Whether to print analysis of projection for read-in guesses:

0 Default (122 if using symmetry in diagonalization, 222 otherwise).
1 Yes.
2 No.
10 Symmetrically orthogonalize core and valence occupieds together.
20 Symmetrically orthogonalize core and valence occupieds separately.
100 Always project virtuals.
200 Only project virtuals for CAS.


Whether to read energy from chk during Guess=Read (i.e., with SCF=Skip):

0 Default(No).
1 Yes.


Store dispersion energy and derivatives as total?

0 Default (No).
1 Yes.


0 Default (check ILSW for whether ONIOM or QM/MM-style).
1 ONIOM-style, so include.
2 Do not include.


Copy MOs from chk file to reference phase file on rwf. Reference CIS/TD amplitudes are also copied, if found on the chk file.

0 Default(No).
1 Copy.
10 Flip sign of MOs.
20 Flip sign of amplitudes.
30 Flip sign of both MOs and amplitudes.

Last updated on: 21 October 2016. [G16 Rev. C.01]