# Overlay 6

IOp(6/7)

Printing of MOs.

0 | Default: 1 for molecules, 2 for PBC. |

1 | Print the occupied and first 5 virtual MOs. |

2 | Do not print any MOs. |

3 | Print all MOs. |

10 | Biorthogonalize unrestricted MOs. |

100 | Save biorthogonalized MOs over canonical ones. |

IOp(6/8)

Density matrix. Default: No-print. See below for values.

IOp(6/9)

Full population analysis. Default: Print. See below for values.

IOp(6/10)

Gross orbital charges. Default: Print. See below for values.

IOp(6/11)

Gross orbital type charges. Default: No-print. See below for values.

IOp(6/12)

Condensed to atoms. Default: Print. See below for values.

IOp(6/8-12)

These options are print/no-print options. The possible values are:

0 | Default. |

1 | Print the normal amount. |

2 | Do not print. |

3 | Print verbosely. |

IOp(6/13)

Whether to save computed electric field on disk for use in Tomasi RF calculations.

0 | Default (No). |

1 | Yes. |

2 | No. |

IOp(6/14)

L602: Specification of other properties to be calculated.

0 | Default (1). |

1 | Evaluate the electric potential, the electric field, and the electric field gradient at each center. |

2 | Evaluate the potential and the electric field at each center. |

3 | Evaluate only the potential at each center. |

4 | Evaluate none. |

IOp(6/15)

Specification of additional centers. If more than one of these is requested, the lists are in separate input sections in the order listed below.

0 | No additional centers. Evaluate the properties only at each atomic center. |

1 | Read additional centers. One card per center with the X, Y, and Z coordinates in Angstroms (free format). |

2 | Read in coordinates as for 1. Starting at each point, located the nearest stationary point in the electric potential. |

4 | Read in a set of cards specifying a grid of points at which the electric potential will be computed. Two forms of specifications are below. |

8 | Do potential-derived charges. |

16 | Constrain the dipole in fitting charges. |

32 | Read in centers at which to evaluate the potential from the RWF. |

128 | Read grid; do not default cube. |

#### Grid specifications for option 4

A. Evenly spaced rectangular grid. Three cards are required:

KTape,XO,YO,ZO | —output unit and coordinates of one corner of grid. If KTape is 0, it defaults to 51. |

N1,X1,Y1,Z1 | —number of increments and vector. |

N2,X2,Y2,Z2 | —number of increments and vector. |

N1 records will be written to unit KTape, with N2 values in each record.

B. An arbitrary list of points. Only one card is needed: N,NEFG,LTape,KTape.

The coordinates of N points in Angstroms will be read unit LTape in format (3F20.12). The potential (NEFG=3), potential and field (NEFG=2), or potential, field, and field gradient (NEFG=1) will be computed and written along with the coordinates to unit KTape in format (4F20.12). Thus if NEFG=3 for each point there will be 4 cards written per point, containing:

X-coord,Y-coord,Z-coord,Potential |

X-field,Y-field,Z-field,XX-EFG |

YY-EFG,ZZ-EFG,XY-EFG,XZ-EFG |

YZ-EFG |

Note that either form of grid should be specified with respect to the standard orientation of the molecule.

IOp(6/16)

L602: Cutoffs.

0 | Use full accuracy in calculations at specific points, but use sleazy cutoffs in mapping a grid of points. |

1 | Do all points to full accuracy. |

IOp(6/17)

L602: Debugging control.

0 | Compute all contributions to selected properties. |

1 | Compute only the nuclear contribution. |

2 | Compute only the electronic contribution. |

-N | Compute only the contribution of shell N. |

IOp(6/18)

Whether to update dipole RWF.

0 | Yes. |

1 | No. |

IOp(6/19)

Whether to rotate exact polarizability before comparing with approximate (which will be calculated in the standard orientation). This is like IOp(6/9) in L9999.

0 | Default, same as 1. |

1 | Exact is still in standard orientation; use as-is. |

2 | Exact is already in z-matrix orientation, so rotate. |

IOp(6/20)

How to do electrostatic-potential derived charges.

0 | Default (1). |

-1 | Read a list of points at which to fit, one per line. |

1 | Merz-Kollman point selection. |

2 | CHELP point selection. |

3 | CHELPG point selection. |

4 | MK but with 2xUFF radii. |

5 | Hu, Lu, and Yang point selection/weighting. By default, HLY’s atomic densities are used. These are available only up to Ar. |

00 | Default radii are those defined with the selected method. |

10 | Force Merz-Kollman radii. |

15 | Use Gaussian’s atomic density expansions instead of HLY’s. Gaussian’s are defined for all elements up to 112. |

20 | Force CHELP (Francl) recommended radii. |

30 | Force CHELPG (Breneman) recommended radii. |

40 | Force 2xUFF Radii. |

100 | Read in replacement radii for selected atom types as pairs (IAn,Rad) or (Symbol,Rad), terminated by a blank line. |

200 | Read in replacement radii for selected atoms as pairs (I,Rad), terminated by a blank line. |

1000 | Fit united atoms (heavy atoms only) rather than all atoms. |

00000 | Default (10000). |

10000 | Use only active atoms in the fit. |

20000 | Use all atoms in the fit. |

30000 | Fix the charges of all atoms with a non-zero MM charge. |

IOp(6/22)

L601, L602, L604: Selection of density matrix.

-1x | Read density matrices from .checkpoint file. |

+1x | Read density matrices from .checkpoint file. |

-5 | All available transition densities. |

-4 | Transition density between the states given by IOp(6/29) and IOp(6/30). |

-3 | Density for the excited state given by IOp(6/29). |

-2 | Use all available density matrices. |

-1 | Use the density matrix for the current method, or the HF density if the one for the current method is not available. |

N≥0 | Use the density matrix for method N (see Link 1 for the numbering scheme). |

IOp(6/23)

L604: Density values to evaluate over grid.

0 | Default (same as 3). |

1 | Density values. |

2 | Density values and gradients. |

3 | Density values, gradients and divergence. |

IOp(6/24)

Frozen core.

-N | Freeze N orbitals. |

0 | Default (Yes). |

1 | Yes. |

2 | No. |

IOp(6/25)

L601: Whether to compute Coulomb self-energy.

0 | No. |

1 | Yes, classically (including self terms — requires 2e integrals, O(N^{4})). |

2 | Yes, quantum mechanically (no self terms — requires 2e integrals, and only available for HF. O(N^{5})). |

IOp(6/26)

L602, L604: Which density to use.

0 | Default (same as 1). |

1 | Total. |

2 | Alpha. |

3 | Beta. |

4 | Spin. |

IOp(6/27)

Choice of population analysis.

0 | Default (12). |

1 | Don’t do Mulliken populations. |

2 | Do Mulliken populations. |

10 | Don’t do bonding Mulliken populations. |

20 | Do bonding Mulliken populations. |

100 | Do minimal population analysis. |

1000 | Read in weightings for atoms pairs for unequally split Mulliken. |

IOp(6/28)

Mark SCF density as current density.

0 | No: save SCF density, but do not mark. |

1 | Yes: mark as well. |

IOp(6/29)

Excited state to use if requested by IOp(6/22).

IOp(6/30)

2nd excited state for transition density.

0 | Transition density between state IOp(6/29) and g.s. |

N | Transition density between state IOp(6/29) and state N. |

IOp(6/31)

Whether to determine natural orbitals from densities.

0 | No. |

1 | Yes, using total density. |

2 | Yes, using alpha and beta separately for UHF. |

3 | Store only alpha NOs. |

4 | Store only beta NOs. |

5 | Use spin density. |

IOp(6/32)

L609: Control parameters for COVBON (not to be changed under most circumstances).

100000*IPrSma+10000*MItLoc+1000*ITlLoc+100*IDcInt+IPrLoc, where:

IPrSma | When printing MOs in terms of AOIMs, include only MOs with occupancies per spin greater than 10^{-IPrSma} and AOIMs with squares of coefficients greater than 10^{-IPrSma} (1…9, the default of 0 implies printing of all MOs and AOIMs). |

MItLoc | MItLoc*NOrb*(NOrb-1)/2 is the maximum number of iterations in localization of (spin) orbitals (1…9, default 6). |

ITlLoc | 10.^{-ITlLoc} is the convergence criterion for (spin)orbital localization (1…9, default 9). |

IDcInt | Localized (spin)orbitals with atomic occupancies less than 0.01*IDcInt are interpreted as lone pair MOs rather than bond MOs (1…99, default 10). |

IPrLoc | 0: Print the atomic occupancies of localized (spin)orbitals (default). 1: Do not print the atomic occupancies. |

L605, L606: naming of RPAC interface file.

0 | Make this a scratch file. |

1 | Name this file ‘rpac.11’ |

IOp(6/35)

L609: What to do:

0 | Determine attractors, attractor interaction lines, ring points, and cage points. |

1 | Determine zero-flux surfaces (IDoZrF). |

2 | Compute charges of AIMs (IDoAtC). |

4 | Compute kinetic energies and multipole moments of AIMs (IDoPrp). |

10 | Compute energies of electrostatic interactions between AIMs (IDoPot). This precludes calculations of atomic property derivatives with respect to nuclear displacements. |

100 | Compute atomic overlap matrices (IDoAOM). |

200 | Compute other atomic matrix elements (IDoAMa). |

400 | Include zero-flux surface relaxation terms in all atomic matrix elements (IDoSRe). |

1000 | Compute derivatives of atomic properties with respect to electric field (IDoSeP). Note that IDoSRe should be set to 1 in order to obtain correct results! Also note that analytical polarizabilities have to be available but force constants have to be absent! |

2000 | Compute derivatives of atomic properties with respect to nuclear displacements as well (IDoNuD). Note that analytical force constants have to be available! |

10000 | Compute localized orbitals and bond orders (IDoLoc). |

20000 | Compute atomic orbitals in molecule (IDoAOs). |

100000 | If necessary, augment valence electron densities with relativistic core contributions, which is a default anyway (IHwAug = 0). |

200000 | If necessary, augment valence electron densities with non-relativistic core contributions (IHwAug = 1). |

400000 | Abort if pseudo-potentials have been used (IHwAug = 3). |

1000000 | Reduce accuracy so atomic charges can be computed more rapidly (IQuick). No other properties can be calculated. This option sets IPrNDe=5, IPrNA t= 5, and IEpsIn = 100. |

2000000 | Use numerical instead of analytic integration. |

3000000 | Use numerical instead of analytic integration and use reduced cutoffs. |

4000000 | Full accuracy and analytic integration. |

IOp(6/36)

L609: Control parameters for neglect of orbitals and primitives.

10000*INoZer+100*IPrNDe+IPrNAt, where…

INoZer | 0: Ignore (spin)orbitals with zero occupancies (default). 1: Do not ignore (spin)orbitals with zero occupancies. |

IPrNDe | Neglect primitive contributions below 10.^{-IPrNDe} in evaluations of electron density and its derivatives (0…99, default 7). |

IPrNAt | Neglect primitive contributions below 10.^{-IPrNAt} in integrations over atomic basins (0…99, default 7). |

IOp(6/37)

L609: Control parameters for ATINLI, RNGPNT, and CAGPNT (not to be changed under most circumstances).

1000000*MxBpIt+100000*SBpMax+1000*NGrd+LookUp, where…

MxBpIt | Maximum number of iterations in trial path determination (1…99, default 10). |

SBpMax | Maximum value of the control sum (1…9, default 2). |

NGrd | Length of Fourier expansion for the trial path (1…99, default 20). |

LookUp | Number of grid points in critical point search (1…999, default 100). |

IOp(6/38)

L609: Control parameters for ZRFLUX and OIGAPI (not to be changed under most circumstances):

100000*INStRK+10000*IHowFa+1000*IGueDi+100*IPraIn+10*IRScal+IRtFSe

INStRK | 10*INStRK is the number of steps in the Runge-Kutta integrations along gradient paths (1…9, default 2). |

IHowFa | IHowFa is the maximum distance in the Runge-Kutta integrations along gradient paths (1…9, default 5), |

IGueDi | 10.^{-IGueDi} is the initial displacement from the critical point in the Runge-Kutta integrations (1v9, default 6). |

IPraIn | 10.*IPraIn is the cut-off for zero-flux surfaces (1…9, default 2). |

IRScal | IRScal is the scaling factor in the nonlinear transformation used in the intersection search (1…9, default 2). |

IRtFSe | 10.*IRtFSe is the safety factor used in the intersection search (1…9, default 2). |

IOp(6/39)

L609: More control parameters for ZRFLUX and OIGAPI (not to be changed under most circumstances):

1000000*IToler+100000*INInGr+10000*INInCh+1000*IEpsSf+10*IEpsIn+INTrig

IToler | 10.^{-5-IToler} is the tolerance for the intersection search (1…9, default 5). |

INInGr | 10*INInGr is the initial number of grid points in theta and phi in the adaptive integration subroutine (1…9, default 2). |

INInCh | 5+INInCh is the initial number of sampling points in the intersection search (1…9, default 2). |

IEpsSf | IEpsSf is the safety factor used for patches with surface faults in the adaptive integration subroutine (1…9, default 6). |

IEpsIn | 0.0001*IEpsIn is the target for integration error (1…99, default 2). |

INTrig | 10*INTrig is the number of sine and cosine functions in the trial function for surface sheets (1…9, default 2). |

IOp(6/40)

L607: Control.

-2 | Skip NBO analysis. |

-1 | Do only NPA. |

0 | Default (-2). |

1 | Default NBO analysis — don’t read input. |

2 | Read input data to control NBO analysis. |

3 | Delete selected elements of NBO Fock matrix and form a new density, whose energy can then be computed by one of the SCF links. This link must have been invoked with IOp(40) = 0 or 1 prior to invoking it with IOp(40) = 2. |

4 | Read the deletion energy produced by a previous run with IOp(40) = 2 and print it. |

10 | NBO should not delete its internal data file. |

IOp(6/41)

Number of layers in esp charge fit.

0 | Default (4). |

N | N layers, must be ≥ 4. |

IOp(6/42)

Density of points per unit area in esp fit.

0 | Default (1). |

N | Points per unit area. |

IOp(6/43)

Increment between layers in MK charge fit.

0 | Default (0.4/Sqrt(#layers)), where # layers = IOP (6/41) |

N | 0.01*N. |

IOp(6/44)

L604: Type of calculation.

0 | Default, same as 2. |

1 | Compute the molar volume. |

2 | Evaluate the density over a cube of points. |

3 | Evaluate MOs over a cube of points. |

10 | Skip header information in cube file. |

IOp(6/45)

Number of points per Bohr^{3} for Monte-Carlo calculation of molar volume.

-1 | Read from input. |

0 | Default (20). |

N | N points — for tight accuracy, 50 is recommended. |

IOp(6/46)

Threshold for molecular volume integration.

0 | Default — 10^{-3} |

-1 | Read from input. |

N | N*10^{-4}. |

IOp(6/47)

Scale factor to apply to van der Waals radii for the box size during volume integration.

0 | Default. |

N | N*0.01 — for debugging. |

IOp(6/48)

Use of cutoffs.

0 | Default (10^{-6} accuracy for cubes, 1 digit better than desired accuracy for volumes). |

N | 10^{-N}. |

IOp(6/49)

L602, L604: Approximate number of points per side in cube.

0 | Default (80). |

N | N points. |

-1 | Read from cards. |

-2 | Coarse grid, 3 points/Bohr. |

-3 | Medium grid, 6 points/Bohr. |

-4 | Fine grid, 12 points/Bohr. |

-N>4 | Grid using 1000 / N points/Bohr. |

IOp(6/50)

Whether to write Antechamber file during ESP charge fitting.

0 | Default (No). |

1 | Yes. |

IOp(6/51)

Whether to apply Extended Koopman’s Theorem (EKT).

0 | Default (No). |

N | Yes, on non-SCF densities, up to N IPs and EAs. |

-1 | Yes, on non-SCF densities, all possible IPs and EAs. |

-2 | No. |

IOp(6/52)

L609: Number of radial integration points.

0 | Default (100). |

N | N. |

IOp(6/53)

L609: Distribution of radial points.

0 | Default (cubic). |

N | Polynomial of order N. |

IOp(6/54)

Maximum number of domains.

0 | Default (100000). |

N | N. |

IOp(6/55)

L609: Number of inner angular points in numerical integration.

-1 | 0(no inner sphere). |

0 | 302. |

N | N point Lebedev grid (see AngQad). |

IOp(6/56)

L608: Whether to read in density matrix from input stream.

0 | No. |

1 | Yes. |

IOp(6/57)

Whether to generate data over a grid using the total SCF density.

0 | No. |

1 | Yes, read in name for output file. |

2 | Yes, also read in name for input file with a different grid and compare. |

3 | Output in the form of data statements. |

4 | Fit atomic density to Gaussians. |

5 | Fit atomic density to Gaussians, forcing positive definiteness. |

IOp(6/58)

Grid to use in generating tables of density and potential if IOp(57) = 1–3. Must be an unpruned grid.

0 | Default (99001). |

If IOp(57) = 4–5, whether to remove primitives which have all zero coefficients in the expansion:

0 | Default (1). |

1 | Yes. |

2 | No. |

IOp(6/59)

Approximations to Exc

-1 | Test superposition of atomic densities using L608: |

0 | Do correct energies. |

1 | Do correct energies and 0th order approximation. |

2 | Do correct energies and 0th-1st order approximations. |

3 | Do correct energies and 0th-2nd order approximations. |

IOp(6/60–62)

Over-ride standard values of IRadAn, IRanWt, and IRanGd. The default is 3 steps smaller grid for HLY charges in L602 and the global default otherwise.

IOp(6/63)

L608: Suppress number of electrons test in XC quadrature (for debugging with small grids):

0 | Default (do test). |

1 | Suppress test. |

2 | Do test as usual. |

IOp(6/64)

Natural Chemical Shielding Analysis.

0 | No. |

1 | Yes, of isotropic value. |

2 | Yes, of diagonal tensor elements and isotropic value. |

3 | Yes, of all tensor components. |

IOp(6/65)

Threshold for printing of NCS contributions.

-1 | Zero. |

0 | Default (1 pmm). |

N | N/1000 ppm. |

IOp(6/72)

L602: Whether to read isotopes for hyperfine interactions and do hyperfine terms.

0 | Default (1). |

1 | Yes, if open-shell, NMR data is available, and other terms are being computed. |

2 | No. |

3 | Yes, regardless of other terms. |

4 | Yes, reading isotopes. |

IOp(6/73)

Whether to save orbitals from NBO.

0 | Default (No). |

1 | Save NBOs in place of regular MOs. |

2 | Save NLMOs in place of regular MOs. |

3 | Save NLMO occupieds and NBO virtuals. |

10 | Suppress re-orthogonalization. |

110 | Suppress sorting. |

IOp(6/74)

Whether to use Gaussian connectivity in choosing Lewis structure for NBO.

0 | Default (use if present and choose is selected in NBO input). |

1 | Use. |

2 | Don’t use. |

IOp(6/75)

L602: Model for CM2 charges.

IOp(6/76)

L607: Threshold for linear dependence.

0 | Default (1.D-6). |

N | 10^{-N}. |

IOp(6/77)

0 | None. |

-1 | 2.d-4. |

N | N * 10^{-5}. |

IOp(6/78)

Use MOs instead of density in AtmTab.

0 | Default (2). |

1 | Use density. |

2 | Use MOs. |

IOp(6/79)

Whether to calculate Hirshfeld charges.

0 | Default (No). |

1 | Yes. |

2 | No. |

3 | Yes, do atom-atom electrostatic interactions as well. |

10 | Do iterative charges. |

20 | Do iterative charges and read initial values. |

100 | Do partitioning of density by abelian irrep. |

NNNxxx | Maximum number of iterations. Default is 50. |

IOp(6/80)

Whether to calculate Lowdin charges and Mayer bond orders.

0 | Default (No). |

1 | Yes. |

2 | No. |

IOp(6/81)

Print kinetic energy of orbitals?

0 | Default (yes, if doing other orbital results). |

1 | Yes, for the top 5 occupieds and lowest 5 virtuals. |

2 | No. |

3 | Yes, for all orbitals. |

IOp(6/82)

Tensors for hyperfine spectra.

0 | Default, compute if there are 100 or fewer atoms. |

1 | Compute QEq tensors and for open-shell systems compute isotropic and anisotropic splitting tensors. |

2 | Do not compute tensors. |

IOp(6/83)

Orbital angular momentum analysis.

0 | Default (No). |

1 | Yes, do total angular momentum contribution to each MO. |

10 | Report the largest atomic d and f contributions to orbitals specified by IOp(6/84). |

20 | Report the largest transition metal atomic d and f contribs. to orbitals specified by IOp(6/84). |

30 | Read a list of atoms whose d and f contributions will be analyzed. |

90 | Do not do atomic d and f contributions. |

100 | Report the population of each angular momentum on each atom. |

IOp(6/84)

Orbitals to analyze for d and f contributions.

-1 | All orbitals. |

0 | Just occupied orbitals. |

N | Occupieds plus lowest N virtuals. |

IOp(6/86)

Computation of multipole moments.

0 | Default (1, except for PBC and old semi-empirical). |

1 | Calculate with DipInt. |

2 | Use stored moment operators. |

IOp(6/87)

L608: Accuracy criterion in Fock matrix formation

0 | Default. |

N | 10^{-N} |

IOp(6/88)

Thresholds for orbital atomic angular momentum printing.

0 | Default (10%). |

NN | At least NN % to print contribution from L on a particular atom. |

IOp(6/89)

Do Natural Transition Orbital Analysis.

0 | No. |

1 | Yes, if ground to excited transition density requested. |

10 | Save over canonical MOs. |

IOp(6/90)

Whether to include p’s as valence for transition metals and actinides during NBO analysis.

0 | Default (Yes). |

1 | Yes. |

2 | No. |

IOp(6/91)

Whether to compute electron-electron spin-spin coupling.

0 | No. |

1 | Yes, if multiplicity >2. |

IOp(6/92)

Thresholds for HLY charge fitting.

0 | Default (Tiny=1.d-8, ThrGrd=1.D-8) |

MMNN | Tiny=10^{-MM}, ThrGrd=10^{-NN}. |

IOp(6/93)

Reference density for HLY charge fitting.

-1 | Zero. |

0 | Exp(-9) |

N | N/100. |

IOp(6/94)

Sigma parameter for HLY charge fitting.

0 | 0.8. |

N | N/1000. |

IOp(6/95)

L608: Whether to diagonalize Fock matrices.

0 | Default (No). |

1 | Yes, with Davidson. |

2 | Yes, with DiagDN. |

IOp(6/96)

Analyze all orbitals by atom and angular momentum contribution.

0 | Default (No). |

-2 | Highest 10 occupieds and lowest 10 virtuals. |

-1 | Yes, for all orbitals. |

N | For highest N occupieds and lowest N virtuals. |

IOp(6/113)

L612: Which external method to use.

0 | Default (1). |

N | Command N in file 747. |

IOp(6/114)

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. |

IOp(6/120)

Store nuclear repulsion energy as total energy? (Here, store only the nuclear contribution to the dipole moment).

0 | Default (no). |

1 | Yes. |

IOp(6/124)

L612: Options for External.

IOp(6/125)

L612: Options for unformatted i/o file.

IOp(6/126)

L612: IDefCm for external.

-1 | Same as 0. |

0 | Default to Gau_External. |

1 | Default to runnbo6. |

IOp(6/127)

Whether to compute BEBO energy corrections.

0 | Default (1 if parameters available). |

1 | Yes. |

2 | No. |

00 | Default (10). |

10 | Use number of pairs (including core) rather than number of lone pairs. |

20 | Use number of lone pairs. |

IOp(6/128)

L608: Compute core and valence energies.

0 | Default (01). |

1 | Do regular calculations. |

10 | Do core-valence. |

11 | Do both. |

IOp(6/129)

Whether to do DCT charge transfer analysis on the selected excited state densities:

1 | Do the analysis if excited state densities are available, and for the relaxed excited state density if this was selected. |

NNNx | Do a maximum of NNN matrices at a time. |

Last updated on: 30 August 2022. [G16 Rev. C.01]