Assume that you divide the whole system as AB, the so-called GEDT is essentially the absolute fragment charge of A or B. You can enter main function 7, use option -1 to define the fragment, and then use corresponding option to choose a method (e.g. ADCH, Mulliken) to compute atomic charges, then the fragment charge will also be outputted.Both Gaussian and Multiwfn support a set of methods for computing atomic charges, while Multiwfn is much more powerful. For the same method, usually there is no evident difference in result for the two programs.
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