Charges

Default Atomic Charge Analysis

By default BAND computes the following atomic charge analyses:

  • Hirshfeld Charges [69, 70]
  • Voronoi Deformation Charges (VDD, Voronoi Deformation Density)
  • Mulliken Charges (note: not calculated for Spin-Orbit calculations)
  • CM5 (Charge Model 5) [71]

These atomic charges are printed to the output file and can be visualized using the ADFView 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 [True | False]
   Iterations integer
   SmallDensity float
   UseStartDensity [True | False]
End
GridBasedAIM
Type:Block
Description:Invoke the ultra fast grid based Bader analysis.
Enabled
Type:Bool
Default value:False
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:False
Description:Whether the analysis is performed on the startup density (True) or on the final density (False). 
AIMCriticalPoints
   Enabled [True | False]
   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:False
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.