# Charges¶

BAND always prints a number of charge analyses. Namely the Voronoi charges, the Mulliken analysis, and the Hirshfeld charges. The calculation comes at virtually no cost, so there are no keys associated with it. This is different for the Bader analysis.

GridBasedAIM (block-type)

Invoke the ultra fast grid based Bader analysis.[33, 34]

GridBasedAIM
{SmallDensity rhosmall }
{Iterations n }
{UseStartDensity [false | true] }
End

SmallDensity
(Default: 1e-6) Where rhosmall is the value below which the density is ignored. This should not be chosen too small because it may lead to unassignable grid points.
Iterations
(Default: 40) The number n determines the maximum number of steps that may be taken to find the nuclear attractor for a grid point.
UseStartDensity
(Default: false) handles whether the analysis is performed on the startup density (true) rather than on the final density (false).
AIMCriticalPoints (block-type)

Also the critical points of the density can be determined. The algorithm starts from a regular mesh of points, and from each of these it walks towards its corresponding critical point.

AIMCriticalPoints
{ GridSpacing space }
{ eqvPointsTol tol }
End

GridPadding
(Default: 0.7 Bohr) pad determines how much extra space is added to the starting guess domain in the search for the critical points.
GridSpacing
(Default: 0.5 Bohr) The variable space determines the distance between the initial trial points.
eqvPointsTol
(Default: 0.27 Bohr) tol is used as a criterion to whether or not two critical points are the same.

Note

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