the one-electron LFSE-type formula.
A numerical experiment enabled by the ADF code [38] is the removal
of virtual fragment orbitals in selected fragments, hindering
in this way the electron structure rearrangements inside the components
of the given unit, during the formation of the bond, or suspending
the donor activity from the occupied MOs of neighbor
fragments towards the deleted empty functions. The results are
presented in Table 7.