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


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 Invoke the ultra fast grid based Bader analysis.
Enabled
Type: Bool False Invoke the ultra fast grid based Bader analysis.
Iterations
Type: Integer 40 The maximum number of steps that may be taken to find the nuclear attractor for a grid point.
SmallDensity
Type: Float 1e-06 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 False Whether the analysis is performed on the startup density (True) or on the final density (False).
AIMCriticalPoints
Enabled [True | False]
EqvPointsTol float
GridSpacing float
End

AIMCriticalPoints
Type: Block 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 False 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 0.27 Bohr 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 0.7 Bohr How much extra space is added to the starting guess domain in the search for the critical points
GridSpacing
Type: Float 0.5 Bohr 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.