Charges

Default Atomic Charge Analysis

By default BAND computes the following atomic charge analyses:

  • Hirshfeld Charges 1 2

  • Voronoi Deformation Charges (VDD, Voronoi Deformation Density)

  • Mulliken Charges (note: not calculated for Spin-Orbit calculations)

  • CM5 (Charge Model 5) 3 4

These atomic charges are printed to the output file and can be visualized using the AMSview GUI module.

A more detailed output of the atomic charges can be printed by specifying following print option (note: in Band 2017 and previous versions this detailed output was printed by default):

Print AtomicChargesDetails

Bader Analysis (AIM)

The QTAIM (Quantum Theory of Atoms in Molecules), also known as Bader Analysis can be enabled in the GridBasedAIM input block:

GridBasedAIM
   Enabled Yes/No
   Iterations integer
   SmallDensity float
   UseStartDensity Yes/No
End
GridBasedAIM
Type

Block

Description

Invoke the ultra fast grid based Bader analysis.

Enabled
Type

Bool

Default value

No

GUI name

Bader (AIM): Atomic properties

Description

Invoke the ultra fast grid based Bader analysis.

Iterations
Type

Integer

Default value

40

Description

The maximum number of steps that may be taken to find the nuclear attractor for a grid point.

SmallDensity
Type

Float

Default value

1e-06

Description

Value below which the density is ignored. This should not be chosen too small because it may lead to unassignable grid points.

UseStartDensity
Type

Bool

Default value

No

Description

Whether the analysis is performed on the startup density (True) or on the final density (False).

AIMCriticalPoints
   Enabled Yes/No
   EqvPointsTol float
   GridPadding float
   GridSpacing float
End
AIMCriticalPoints
Type

Block

Description

Compute the critical points of the density (Atoms In Molecules). The algorithm starts from a regular mesh of points, and from each of these it walks towards its corresponding critical point.

Enabled
Type

Bool

Default value

No

GUI name

: Critical points and bond paths

Description

Compute the critical points of the density (Atoms In Molecules). The algorithm starts from a regular mesh of points, and from each of these it walks towards its corresponding critical point.

EqvPointsTol
Type

Float

Default value

0.27

Unit

Bohr

Description

If the distance between two critical points is smaller than this value, the two critical points are considered to be the same point.

GridPadding
Type

Float

Default value

0.7

Unit

Bohr

Description

How much extra space is added to the starting guess domain in the search for the critical points

GridSpacing
Type

Float

Default value

0.5

Unit

Bohr

Description

The distance between the initial trial points.

Note

The Bader (AIM) analysis is performed on the fitted density (see ZlmFit). We advise to use a Good (or better) ZlmFit quality.

References

1

F.L. Hirshfeld, Bonded-atom fragments for describing molecular charge densities, Theoretica Chimica Acta 44, 129 (1977)

2

K.B. Wiberg and P.R. Rablen, Comparison of atomic charges derived via different procedures, Journal of Computational Chemistry 14, 1504 (1993)

3

A.V. Marenich, S.V. Jerome, C.J. Cramer, D.G. Truhlar, Charge Model 5: An Extension of Hirshfeld Population Analysis for the Accurate Description of Molecular Interactions in Gaseous and Condensed Phases, Journal of Chemical Theory and Computation 8, 527 (2012)

4

C.A. Peeples and G. Schreckenbach, Implementation of the SM12 Solvation Model into ADF and Comparison with COSMO, Journal of Chemical Theory and Computation 12, 4033 (2016)