For FDE-diab and FDE-ET computations, locally modified versions of the Adf program and the PyAdf scripting framework were used. All calculations employed the TZP basis set from the Adf program library and the PW91 XC functional with the conjoint kinetic-energy functional PW91k . Mutual relaxations of subsystem densities were taken into account applying freeze-and-thaw cycles . Three such cycles were found sufficient to obtain accurate electronic densities (see also Ref. ).