Hi, I am using a relatively high level of SAPT, sapt2+3(CCD)δMP2/aug-cc-pwcvtz-pp and we find positive induction energy for some simple systems, at short distance. For instance Xe-Xe. Could it be due to the pseudopotential? I see the same effect in Xe-Kr but not for Kr-Kr.
David van der Spoel, Uppsala University.