Dear Tian,
OK and thank you so much. Your kind attention is highly appreciated.

Sincerely yours,
Saeed

I don't know, I have no experience in using these keywords.

Dear Tian,
Many thanks for your kindness to answer my question with highly valuable recommendation.
But, do you know what is the reason for such behaviour of Gaussian when one uses a solvation approach as I described?

Sincerely,
Saeed

I never use SC,DoVacuum. The most reasonable way of calculating solvation free energy is taking the difference between the electronic energies with and without implicit solvation model.

Dear Tian,

You know much better than me when solvation energy is requested to be computed by Gaussian through:

#Method/Basis set SCRF(SMD,SC,DoVacuum,Solvent=XX

Gaussian prints out "Delta G (Solvation). We know that within this type of calculations there is not temperature and entropic contribution consideration and all reported terms include electronic energy plus non-electrostatic and electrostatic interactions. So, one excepts Gaussian prints out Delta(E solvation) not Delta G(solvation) which, in the current computation does not have any sense. By the way I personally always use this value as Delta_E_solvation and not Delta_G_solvation even though Gaussian emphasizes on Delta_G_solvation.
If possible, please let me know why Gaussian erroneously employs a wrong notation, Delta_G_solvation instead a quite reasonable and expected Delta_E_solvation.

Sincerely,
Saeed