The Ziegler-Rauk [31] energy decomposition analysis (EDA)
implemented in ADF does not discriminate a charge transfer term,
which is, otherwise, explicit in the Kitaura–Morokuma scheme
[32]. In the attempt to separate the charge transfer effects, we will
use, in the following, fragments with fractional charge, preliminarily
prepared by a procedure equivalent to the electronegativity
equalization principle [33]. Thus, we will consider a model of partial
interaction consisting in the sum of charge-dependent fragments
and their electrostatic interaction: