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I am trying to calculate the energy of complex molecules with DFT and have a question about the Ahlrichs (Karlsruhe) def2 basis sets.
What is the difference between the def2-SV, def2-SV(P), and def2-SVP? Do they only differ in whether the basis set includes split valence polarization or not?
Def2-SVP has the polarisation functions on all atoms, -SV(P) does not have these functions on the hydrogen atoms and -SV does without them.
In future, you can check on the EMSL Basis Set Exchange It wouldn't give you an answer explicitly, but you can view the basis set for different atoms and see how the different sets vary.
A side note - If your 'complex molecules' aren't too large, consider the larger Def2-TZVP basis set. Errors at the Def2-SVP level can be several kcal which may significantly impact your study. As an alternative, consider the PC-n family of basis sets from Frank Jensen. If the Def2-TZVP set is too large, the double-zeta PC-1 might work well.
