# Controlling printed Output¶

The amount of printed output is regulated with the keys Print, NoPrint, EPrint and Debug. (No)Print and Debug are simple keys, EPrint is a block type key.

Many print options pertain to debugging situations and are included here only for completeness. This section is intended to give a survey of all possibilities. Some items may be mentioned again in other sections where the subject of a particular print switch is discussed.

## Print / NoPrint¶

```
PRINT Argumentlist
Print Argumentlist
NoPrint Argumentlist
```

`Argumentlist`

- A sequence of names separated by blanks or commas. The keys Print and NoPrint may occur any number of times in the input file. The names in the argument list may refer to various items. For some of them printing is normally on, and you can turn them off with NoPrint. For others the default is not printing; use Print to override that.

Follows a list of the recognized items that are applicable in the argument lists, with a short explanation and defaults. Item names must be used exactly as given in the table - abbreviated or elongated forms will not be recognized - but they are not case sensitive.

**Items**

`$ALL`

Default: No

Turns on all print options. This will not be affected by any additional noprint instructions. Be careful: this generates a large amount of output. To be used only for debugging purposes.

`Atdist`

Default: No

Inter-atomic distance matrix at each new geometry (in an optimization)

`Bas`

Default: Yes

General control of output related to elementary basis functions (bas).

`BlockCheck`

Default: No

Intermediate data during the determination of the block length. (see Blocks)

`Blocks`

Default: No

Numerical integrals, consisting of loops over large numbers of points, are split up in loops over blocks of points. The block length is determined by the available amount of workspace. Given this amount, the maximum block lengths, according to memory usage in a few relevant routines, are computed (and printed with this print option) and used to impose upper bounds on the block length actually use.

`Character-Table`

Default: No

Table of characters for the irreducible representations of the point group symmetry.

`Computation`

Default: Yes

Reports progress of the computation, with (concise) info about each SCF cycle and each Geometry update in an optimization.

`Core`

Default: No

Description of the frozen core: frozen core expansion functions (corbas) and the expansion coefficients for the frozen orbitals. This printing can only be activated if Functions is also

*on*, otherwise it is ignored.`CoreOrt`

Default: No

The valence basis set contains auxiliary Core Functions. They are not degrees of freedom but are used solely to ensure orthogonalization of the valence set to the frozen Core Orbitals. The orthogonalization coefficients and some related overlap matrices are printed.

`CoreTable`

Default: No

Internally the charge density and potential of the atomic frozen cores are processed as tables with values for a sequence of radial distances. A few initial and a few final values from these tables are printed, along with the (radial) integral of the core density, which should yield the number of core electrons.

`EKin`

Default: No

At the end of SCF: Kinetic energy of each occupied MO.

`EndOf`

Default: No

Flags the exit from a few major routines, with cpu times used in these modules. Primarily a debug tool.

`EPauli`

Default: Yes

The repulsive Pauli term in the bonding energy (also called exchange repulsion) with its decomposition in density functional (lda and nl) and Coulomb terms.

`Fit`

Default: Yes

General control of output related to the density fitting.

`Fmat`

Default: No

Fock matrix computed at each cycle of the SCF.

`FmatSFO`

Default: No

Fock matrix (and overlap matrix) in the basis of symmetrized fragment orbitals (SFOs). This option requires the FULLFOCK and ALLPOINTS keyword to be present in the input. The matrix is printed only at the last SCF cycle. Use 1 iteration in the SCF for the Fock matrix at the first SCF cycle.

`ForceConstants`

Default: Yes

Force constants matrix (Frequencies run only)

`FreqHess`

Default: No

matrix of force constants (Frequencies run) after each applicable step in its processing: transformation from/to Cartesian and Z-matrix coordinates, symmetrizations, ...

`Frag`

Default: No

General control of output related to build-molecule-from-fragments.

`Functions`

Default: Yes

List of employed Slater-type exponential basis functions and fit functions.

`Gradients`

Default: No

detailed info of computed energy gradients (in optimization runs)

`Group-Operators`

,Default: No- 3*3 matrices of point group symmetry operators, with the axis and angle of rotation
`HessEig`

Default: No

Eigenvalues of the Hessian in each cycle of a Geometry Optimization. The print-out in the intermediate cycles is suppressed if output of updated coordinates etc. is turned off (see the EPRINT subkey Repeat (option GeoStep).

`Idfree`

Default: No

List of free atomic coordinates with indication whether they are optimization coordinates (this info is also contained in the output of new atomic coordinates at each step of an optimization)

`Inertia`

Default: No

Warning message in the log file in case of zero product of moments of inertia (this may correctly be the case for certain molecules)

`Inputkeys`

Default: No

List of keys that were specified in input, together with some of the associated data. The list is printed directly after the echo of the Input File, before the header with ADF program information. A few special keys will not be echoed: (No)Print,(No)Skip, Allow.

`Irrep-Matrices`

Default No

Irreducible representation matrices

`Logfile`

Default: Yes

At the end of the calculation a copy of the log file is appended to standard output

`low`

Default: No

Construction of the LOW basis from the elementary BAS functions and from the SFOs: combination coefficients

`lowMO`

Default: No

MOs are printed in the LOW (Lowdin) representation, in the RESULTS section

`OvlBAS`

Default: No

overlap matrices processed during the construction of the LOW basis. Only printed in case OLDORTHON is used in input.

`Parser`

Default: No

Most input records are echoed twice (at the very beginning of output). First the original version, then the parsed version in which expressions have been replaced, redundant blanks removed, etc. The parsed version is what the program really uses as input. Comment blocks, and function definitions (in define blocks) are not parsed, and are not affected by this switch. If the print switch is off only the original, non-parsed input record is echoed in output. This print switch affects only the part of input after its occurrence.

`Pmat`

Default: No

The density matrix (in Lowdin representation) in each cycle of the SCF.

`QMpot`

Default: Yes

At the end of the SCF for each atom the electrostatic potential at its nucleus (excluding its own contribution of course).

`RedCrd`

Default: No

Redundant Coordinates used in the construction of the initial - force field derived - Hessian

`RedCrdBonds`

Default: No

Atom-atom bonds determined for the construction of the initial Hessian

`RedCrdH`

Default: No

Hessian in the redundant coordinates representation

`SCF`

Default: Yes

Controls the information about progress of the SCF procedure. Applies only if the print switch computation is on.

`sdiis`

Default: No

Expansion coefficients applied by the DIIS procedure during the SCF.

`sdiismat`

Default: No

Turns on sdiis(see above)

*and*prints the*error vector*constructed by the DIIS routine (this is the commutator of the Fock matrix and the Density matrix). This is used to determine the DIIS expansion coefficients and to assess convergence.`SFO`

Default: depends on system size

General control of SFO-related output (if SFO subkey of key EPRINT is used). If turned off, (almost) all such output is suppressed. If on, such printing is controlled by the eprint subkey SFO. The default depends on the system size: if the number of primitive STOs < 1000, the default is Yes, else No.

`Smat`

Default: No

Overlap matrix of BAS functions.

`Smearq`

Default: No

Smear parameter - if and when applied - used in the determination of electronic occupation numbers for the MOs, with details of how it works out at every cycle of the SCF. For debugging purposes.

`SpinOrbit`

Default: No

detailed information about how double-group symmetry representations are related to the single group representations

`Tails`

Default: No

In each block of integration points (see Blocks) the evaluation of (Slater-type) exponential functions (basis, fit) is skipped when the function has become negligible for all points in that block due to the distance of those points from the atom where the function is centered. The relative savings due to this distance screening is printed at the first geometry cycle (use debug for printing at all cycles).

`TechPar`

Default: Yes

Technical parameters such as maximum vector length in vectorized numerical integration loops, SCF and Geometry Optimization strategy parameters.

`Timing`

Default: No

Print out of more timing info (in particular with respect to performance of the parallel version of ADF) than is provided by the standard Timing Statistics tables at the end of each output.

`TimingDetail`

Default: No

Similar, but more details.

`TimingTooMuchDetail`

Default: No

Similar, but even worse.

`Workspace`

Default: No

Statistics of calls to the Workspace Manager (memory management).

*Arguments for the keys PRINT and NOPRINT.*

For print switches Frag, Fit, Freq, Geostep, Numint, Repeat, SCF, SFO, TF, see the key EPRINT below.

## Debug¶

The key DEBUG is used to generate extensive output that is usually only relevant for debugging purposes. It operates exactly like the PRINT key but there is no converse: nodebug is not recognized; it would be irrelevant anyway because by default all debug print switches are off.

A list of the possible items for the DEBUG key is given below.

All items of the print list can also be used with the debug key. If they are not mentioned in table III, the meaning is the same as for the print key, but the corresponding output may be generated more often, for instance at every SCF cycle rather than at the last one only.

Item |
Explanation |

Basis | Construction of the orthonormal LOW basis from elementary (BAS) and fragment (FO) basis. |

Core | Core Orthogonalization procedure |

Ekin | Kinetic energy matrices. (compare the print switches EKIN) |

Fit | Construction of the symmetry adapted fit functions |

Fitint | Construction of integrals used in the Fit procedure. |

Freq | Force matrices processed in the computation of frequencies: |

Cartesian and internal representation, before and after symmetrization, | |

etc. (as far as applicable). | |

GeoStep | Geometry optimization procedure. All relevant items. |

Hess | Complete eigensystem of the Hessian during geometry optimizations. |

NumInt | Numerical integration. Very extensive output |

(including the coordinates and weights of all generated points). | |

Pmat | P-matrix (density matrix) during SCF |

and in the ETS analysis program in the BAS representation. | |

Rhofih | Computation of fit coefficients during the SCF. |

SCF | Extensive output during the SCF procedure about many different items. |

See also EPRINT, subkey SCF. | |

SDIIS | All data concerning the DIIS as used during the SCF. |

See ERPRINT, subkey SDIIS. | |

TransitionField | The Transition State procedure to compute and analyze certain terms in the bonding energy. |

The distinct components, the involved transition field Fock matrices, etc. |

## Eprint¶

The key EPRINT is an extended version of the (no)print key, employed for print switches that require more specification than just off or on.

Contrary to what is the case for the keys print and noprint, the key EPRINT must occur only once in the input file; any subsequent occurrences are incorrect and ignored or lead to abort.

```
EPRINT
subkey
subkey
...
end
```

`subkey`

- A subkey-type structure: it consists of a keyword followed by data, so that it functions as a simple (sub)key,
*or*it is a keyword followed by a data*block*which must then end with the word subend.

The subkeys used in the EPRINT data block are called Eprint keys. A complete list of them is given below. All available EPRINT keys are discussed in the schemes below. The enclosing records EPRINT and end are omitted in these schemes.

EPRINT subkeys |
Subject |

AtomPop | Mulliken population analysis on a per-atom basis |

BASPop | Mulliken population analysis on a per-bas-function basis |

Eigval | One-electron orbital energies |

Fit | Fit functions and fit coefficients |

Frag | Building of the molecule from fragments. |

FragPop | Mulliken population analysis on a per fragment basis |

Freq | Intermediate results in the computation of frequencies (see debug: freq). |

GeoStep | Geometry updates (Optimization, Transition State, ...) |

NumInt | Numerical Integration |

OrbPop | (Mulliken type) population analysis for individual MOs |

OrbPopEr | Energy Range (ER) in hartree units for the OrbPop subkey |

Repeat | repetition of output in Geometry iterations (SCF, optimization, ...) |

SCF | Self Consistent Field procedure |

SFO | Information related to the Symmetrized Fragment Orbitals and the analysis |

TF | Transition Field method. |

## Eprint subkeys vs. Print switches¶

Several EPRINT subkeys are merely shortcuts for normal (no)print switches. All such simple subkeys are used in the following way:

```
EPRINT
ESUBKEY argumentlist
END
```

`Esubkey`

- One of the following EPRINT subkeys: Fit, Frag, GeoStep, NumInt, Repeat, SCF, sdiis, SFO, TF, Time.
`argumentlist`

- A sequence of names, separated by delimiters. Each of these names will be concatenated with the esubkey and the combination will be stored as a normal print switch. Example: Frag rot, SFO will be concatenated to fragrot and fragsfo and both will be stored as print switches. All such combinations can also be specified directly with the key PRINT. The example is therefore exactly equivalent with the input specification: print FragRot, Fragsfo****

If any of the names starts with the two characters no, the *remainder* of the name will be concatenated with the EPRINT, but now the result will be stored and treated as a noprint switch. Items that are on by default can in this way be turned off. Example:

```
EPRINT
FRAG noRot Eig
END
```

This turns Rot *off* and Eig *on* for the EPRINT subkey Frag. Equivalent would be:

```
NOPRINT FragRot
Print FragEig
```

Follows a description of all simple EPrint subkeys:

**Fit**

The subkey fit controls output of how the elementary fit functions are combined into the symmetric (A1) fit functions. It controls also printing of the initial (start-up) and the final (SCF) fit coefficients.

```
EPRINT
FIT list
END
```

`list`

- A list of items, separated by blanks or commas. The following items are recognized: Charge, Coef, Comb.
`Charge`

- The amount of electronic charge contained in the fit (start-up), total and per fragment.
`Coef`

- The fit coefficients that give the expansion of the charge density in the elementary fit functions.
`Comb`

The construction of the totally symmetric (A1) fit function combinations from the elementary fit functions.

By default all options are off.

**Frag**

The subkey frag controls output of how the molecule is built up from its fragments.

```
EPRINT
FRAG list
END
```

`list`

- A list of items, separated by blanks or commas. The following items are recognized: Eig, Fit, Rot, SFO.
`Eig`

- The expansion coefficients in elementary functions (bas) of the fragment Molecular Orbitals as they are on the fragment file.
`Rot`

- The rotation (and translation) required to map the master fragment (i.e. the geometrical data on the fragment file) onto the actual fragment which is part of the current molecule. N.B.: if eig and rot are both
*on*, the rotated fragment orbitals are printed also. `Fit`

- The fit coefficients that describe the fitted charge density of the fragments after the rotation from the
*master*fragment on file to the actual fragment. These are the molecular fit coefficients that are used (by default) to construct the total molecular start-up (fitted) charge density and hence the initial Coulomb and XC potential derived from it. `SFO`

- The Symmetry-adapted combinations of Fragment Orbitals that are used in the current calculation. This feature ensures that the definition of the SFOs is printed. This will happen anyway whenever the EPRINT subkey SFO itself is activated. By default all options are off. Remark: SFO analysis in a Spin-Orbit relativistic calculation is implemented only in the case there is one scalar relativistic fragment, which is the whole molecule.

**Freq**

Controls printing of Force matrices and a few more data that are intermediate results in the computation of frequencies after all coordinate displacements have been carried out.

```
EPRINT
FREQ list
END
```

`list`

- contains any of the items SymCoord, DMuRot, Hess.
`SymCoord`

- print the Symmetry Coordinates, both as they are generated, and some related info in their processing later on. The Symmetry Coordinates are symmetry-adapted combinations of Cartesian displacements, with the pure translations and rotations projected out.
`dmuRot`

- info about generating Dipole-Derivative information in transformation between Cartesian and internal coordinate representation as regards the rotational aspects.
`Hess`

processing of the completed matrix of force constants, symmetrization, transformation to other coordinates.

By default all options are off.

Controls output concerning the geometry update method, parameters, energy gradients, etc. It plays no role in a SinglePoint calculation.

**GeoStep**

```
EPRINT
GEOSTEP list
END
```

`list`

- A list of items, separated by blanks or commas. The following items are recognized: Energy, GradientTerms, Gradients, Upd.
`Energy`

- summary of the (bonding) energy and its components as computed in the geometry update procedure.
`Gradients`

- Energy gradients on the free variables. These may be all or some of the Cartesian or the Z-matrix coordinates, depending on the case.
`GradientTerms`

- The decomposition of the gradients in computed terms, as described in the thesis of L.Versluis [7].
`Upd`

parameters used and adapted in the geometry update procedure.

By default Gradients, Upd are on, the other items off.

**NumInt**

Output related to the numerical integration procedure: parameters, generated points, tests on the accuracy of the generated scheme, etc.

```
EPRINT
NUMINT list
END
```

`list`

- A list of items, separated by blanks or commas. The following items are recognized: All, Geo, Ovl, Par, Pnt, Res, Sym, Test.
`All`

- includes all other options and prints in addition the coordinates and weights of all generated points.* This can be a lot of output!*
`Geo`

- geometric data such as boundary planes around the molecule, as they are computed and used in the program section where the point grid is generated.
`Ovl`

- numerically integrated are the auto-overlaps of symmetry-adapted combinations of elementary basis functions SBAS. The deviations from the analytically computed values is printed. The test option, see below, yields a summary of these data: the maximum error and the root-mean-square error.
`Par`

- employed precision parameters, atomic spheres radii etc.
`Pnt`

- the generated
*numbers*of points in each of the subregions processed in the point-generating procedure. `Res`

- results as regards the total number of points, the sum-of-weights and the partitioning of the points in blocks (for segmented vectorization).
`Sym`

- the symmetry operators that are computed directly from the coordinates (irrespective of the input Schönfliess symbol) and that are used to construct thec numerical integration grid in a symmetric fashion.
`Test`

a few external tests are performed after the grid has been generated, such as the numerical integration of the sum-of-fragment densities. See also the norms option.

By default Res and Test are on, the other options off.

**OrbPop**

Specifies that (Mulliken type) population analysis should be printed for individual MOs, both on a per-SFO basis and on a per-bas function basis. The format of the subkey is as follows:

```
EPRINT
ORBPOP TOL=X Nocc Nunocc
SUBEND
END
```

X is the threshold for the SFO coefficient value to include in the listing for the per-SFO analysis. Nocc is the number of the highest occupied and Nunocc is the number of the lowest unoccupied orbitals to analyze.

**OrbPopEr**

Specifies the energy range for the MOs to which the OrbPop key applies. The default range is from -0.7 below the HOMO to 0.2 Hartree above the LUMO. Usage:

```
EPRINT
OrbPopER minEn maxEn
END
```

where minEn and maxEn are both in Hartree, and have the defaults just specified. In order to get information on many more orbitals, simply specify a large negative value for minen and a large positive value to maxen.

**Repeat**

Control the repetition of output in Geometry iterations: optimization, computation of frequencies, transition state search.

```
EPRINT
Repeat list
END
```

`list`

- contains one or more of the following items: NumInt, SCF.
`NumInt`

- Output from the numerical integration procedure, like parameters, numbers of points generated, test data is controlled by the
*numint*subkey (see below). The*repeat*subkey controls whether the output is repeated for all geometries (if the flag is on) or only for the first (if the flag is off). Some concise info is produced (repeatedly) anyway if the print switch computation is on. `SCF`

Controls similarly the SCF output, like population analysis and orbital eigenvalues. If the flag is on, these items are printed at the last SCF cycle in every geometry, otherwise only at the last (in case of an optimization, not in case of a Frequencies calculation).

By default both options are off.

**SCF**

Output during the SCF procedure.

```
EPRINT
SCF list
END
```

`list`

- is a list of items, separated by blanks or commas. The following items are recognized: Eigval, Eigvec, Err, Fmat, Keeporb, MOPop, Occ, Pmat, Pop, Start.
`Eigval`

- Eigenvalues of the one-electron orbitals at the last SCF cycle. In a run with multiple SCF runs (Geometry Optimization,..) this printing occurs only for the last SCF procedure. See also the eigval subkey of EPRINT. (Use debug or the
*repeat*subkey of EPRINT to get output on*all*cycles). `Eigvec`

- MO eigenvector coefficients in the BAS representation. Only printed on the last SCF cycle.
`Err`

- SCF error data which are checked for convergence. By default this takes effect after cycle 25 of the SCF. If the key is set it takes effect at the first cycle. Optionally one may type ErrN,where n is an integer (written directly after Err without a blank in between), in which case the key takes effect at cycle n.
`Fmat`

- Fock matrix in the low representation.
`Keeporb`

- If the KeepOrbitals option is activated (see the key SCF), output is generated whenever this option actually results in a change of occupation numbers as regards the energy ordering.
`Occ`

- concise output of SCF occupation numbers on last SCF cycle if no eigenvalues are printed (see: Eigval).
`moPop`

- Mulliken populations in terms of the elementary basis functions (bas), per MO, for input-specified MOs (see the EPRINT subkey
*orbpop*) `Pmat`

- Density matrix
`Pop`

- General control of bas Mulliken populations. This supervises all printing (whether populations are printed or not) according to the EPRINT subkeys
*atompop, fragpop, orbpop*(the latter only as regards the bas population analysis at the end of the SCF procedure). `Start`

- Data pertaining to the
*first*SCF cycle (of the*first*SCF procedure, in case of an optimization; use*repeat*to get this for*all*SCFs).

By default Eigval, Keeporb, Occ, and Pop are on, the others off.

**SFO**

Information pertaining to the use of Symmetrized Fragment Orbitals (for analysis purposes).

```
EPRINT
SFO list
END
```

`list`

- A list of items, separated by blanks or commas. The following items are recognized: eig, eigcf, orbpop, grosspop, fragpop, ovl.
`Eig`

- The MO coefficients in terms of the SFOs.
`Eigcf`

- idem, but now also containing the coefficients pertaining to the CoreFunctions.
`OrbPop`

- population analysis of individual orbitals. The orbitals analyzed are set with the EPRINT subkey
*orbpop*. `GrossPop`

- Gross populations of the SFOs, split out in symmetry representations. GrossPop is automatically turned on when OrbPop is activated.
`FragPop`

- Population analysis on a per-FragmentType basis. This analysis does in fact not depend on the SFOs (ie, the result does not depend on how the SFOs are defined), but the computation of these populations takes place in the SFO-analysis module, which is why it is controlled by the SFO print option. FragPop output is given per orbital when OrbPop is activated, per symmetry representation when GrossPop is activated, and as a sum-over-all-orbitals-in-all-irreps otherwise (if FragPop is active).
`Ovl`

Overlap matrix of the SFO basis, separately for each symmetry representation.

By default orbpop is on, the other options off.

In a Spin-Orbit calculation the SFO analysis is not yet implemented completely.

*Remark*: the options eig and eigcf replace the previous (now disabled) simple print options eigsfo and eigsfo.

Note that the simple print key SFO controls whether or not the EPRINT subkey *sfo* is effective at all.

**TransitionField**

Part of the bonding energy is computed and analyzed by the so-called Transition State procedure [3, 110]. This has nothing to do with physical transition states, but is related to the Fock operator defined by an average charge density, where the average is taken of the initial (sum-of-orthogonalized-fragments) and the final (SCF) charge density. There is also an analogous term where the average is taken of the sum-of-fragments and the sum-of-orthogonalized-fragments. Various terms, Fock operators and Density Matrices used in this approach may be printed. To avoid confusion with real Transition States (saddle points in the molecular Energy surface) the phrase TransitionField is used here.

```
EPRINT
TF list
END
```

`List`

- A list of items, separated by blanks or commas. The following items are recognized: Energy, Fmat, DiagFmat, FragPmat, DiagFragPmat, F*dPmat, DiagF*dPmat, OrbE.
`Energy`

- Energy terms computed from the TransitionField.
`Fmat`

- TransitionField Fock matrices.
`DiagFmat`

- Idem, but only the diagonal elements.
`FragPmat`

- The molecular P-matrix constructed from the sum-of-fragments.
`DiagFragPmat`

- idem, but only the diagonal elements.
`F*dPmat`

- The TransitionField energy term can be expressed as a Fock operator times the difference between two P-matrices (initial and final density).
`DiagF*dPmat`

- only diagonal elements
`OrbE`

- Orbital energies in the TransitionField.

By default all options are off.

## Other Eprint subkeys¶

We discuss now the remaining EPRINT sub keys that are not simple shortcuts for print switches.

```
EPRINT
Eigval noccup {nvirtual}
END
```

This specifies the *number* of one-electron orbitals for which in the SCF procedure energies and occupation numbers are printed whenever such data is output: the highest noccup occupied orbitals and the lowest nvirtual empty orbitals. Default values are noccup=10, nvirtual=10. If only one integer is specified it is taken as the noccup value and nvirtual is assumed to retain its standard value (10). Printing can be turned off completely with the EPRINT sub key SCF, see above.

**Mulliken Population Analysis**

All population subkeys of EPRINT refer to *Mulliken* type populations.

```
EPRINT
ATOMPOP level
END
```

Populations accumulated per atom.

level must be none, gross or matrix. none completely suppresses printing of the populations; gross yields the gross populations; matrix produces the complete matrix of net and overlap populations. Default value: matrix.

```
EPRINT
BASPop level
END
```

Populations are printed per elementary (bas) basis function. The level options are none, short, gross, matrix. none, gross and matrix are as for atompop.

short yields a summary of BAS gross populations accumulated per angular momentum (*l*) value and per atom.

Default value: gross.

```
EPRINT
FragPop level
END
```

Completely similar to the atompop case, but now the populations per *fragment*. Of course in the case of single-atom fragments this is the same as atompop and only one of them is printed. Default: matrix.

For all three population keys atompop, fragpop and baspop, specification of a higher level implies that the lower-level data, which are in general summaries of the more detailed higher level options, are also printed.

Printing of any populations at the end of the SCF procedure is controlled with the EPRINT sub key *SCF* (pop).

**Population Analysis per MO**

A very detailed population analysis tool is available: the populations *per orbital* (MO). The printed values are independent of the occupation numbers of the MOs, so they are not populations in a strict sense. The actual populations are obtained by multiplying the results with the orbital occupations.

The analysis is given in terms of the SFOs and provides a very useful characterization of the MOs at the end of the calculation, after any geometry optimization has finished. This feature is now also available in a Spin-Orbit coupled relativistic calculation, in the case there is one scalar relativistic fragment, which is the whole molecule.

The same analysis is optionally (see EPRINT subkey *SCF*, option mopop also provided in terms of the elementary basis functions (bas).

```
EPRINT
OrbPop {noccup {nvirtual}} {tol=tol}
subspecies orbitals
subspecies orbitals
...
subend
END
```

`noccup`

- Determines how many of the highest occupied orbitals are analyzed in each irrep. Default noccup=10.
`nvirtual`

- Determines in similar fashion how many of the lowest virtual orbitals are analyzed in each irrep. Default nvirtual=4.
`tol`

- Tolerance parameter. Output of SFO contributions smaller than this tolerance may be suppressed. Default: 1e-2.
`subspecies`

- One of the subspecies of the molecular symmetry group. Can not be used (yet) in a Spin-Orbit coupled calculation.
`orbitals`

- A list of integers denoting the valence orbitals (in energy ordering) in this subspecies that you want to analyze. This overrules the noccup,nvirtual specification for that symmetry representation. In an unrestricted calculation two sequences of integers must be supplied, separated by a double slash (//).

Any subset of the subspecies can be specified; it is not necessary to use all of them. No subspecies must occur more than once in the data block. This can not be used in a Spin-Orbit coupled equation (yet).

A total SFO gross populations analysis (from a summation over the occupied MOs) and an SFO population analysis per fragment type are preformed unless *all* MO SFO-populations are suppressed.

## Reduction of output¶

One of the strong points of ADF is the analysis in terms of fragments and fragment orbitals (SFOs) that the program provides. This aspect causes a lot of output to be produced, in particular as regards information that pertains to the SFOs.

Furthermore, during the SCF and, if applicable, geometry optimizations, quite a bit of output is produced that has relevance merely to check progress of the computation and to understand the causes for failure when such might happen.

If you dislike the standard amount of output you may benefit from the following suggestions:

If you are not interested in info about progress of the computation:

```
NOPRINT Computation
```

If you’d like to suppress only the SCF-related part of the computational report and make the GeometryUpdates related part more concise:

```
NOPRINT SCF, GEO
```

(Keep computation on, so you get at least some info about the GeometryUpdates)

If you don’t want to see any SFO stuff:

```
NOPRINT SFO
```

To keep the SFO *definitions* (in an early part of output) but suppress the SFO-mo coefficients and the SFO overlap matrix:

```
EPRINT
SFO noeig, noovl
END
```

Note: the SFO-overlap matrix is relevant only when you have the SFO-MO coefficients: the overlap info is needed then to interpret the bonding/anti-bonding nature of the various SFO components in an MO.

If you are not interested in the SFO *populations*:

```
EPRINT
SFO noorbpop
END
```