Dear Tian,
Many many thanks for your highly valuable guidance.

Best regards,
Saeed

Dear Saeed,

The CDA analysis in Multiwfn is able to provide overlap integral S(i,j) between fragment orbitals of the two fragments.

Best,

Tian

Dear Tian,
If possible and you kindly let me, I am going to repecfully ask a question.
Please, first, let me present a short explanation about what I am looking for. Consider a given Diels-Alder reaction which is further catalyzed with a catalyst. Suppose our analyses reveal that the catalyzed reaction is preferred over the uncatalyzed reaction due to the least Puli repulsion in the TS associated with the catalyzed reaction (I have performed an EDA such as sobEDA over both TSs to find this matter). Now, I want to find the appropriate occupied fragments orbitals at the TS structure, which are responsible for Pauli repulsion (for example HOMO-n to HOMO from one fragment vs. HOMO-m to HOMO of the other fragment). I do not know how Multiwfn able to perform such a nice analysis. In addition, I want to compute the overlap (S_i,j) between occupied orbitals of two fragments which are responsible for the most Pauli repulsion (If, for example, we can sort the pair orbitals responsibiling for the to 10 values of Pauli repulsion, S(I,j) needs to be computed in these top 10 interactions).
While I hope you kindly accept my highest apology for taking your valuable time with explanations, I would be highly grateful if you guide me to know how such a purpose can be reached by Multiwfn.

Best regards,
Saeed