# How to reproduce the Gaussian 09 SDD basis set in Gamess-US?

I'm trying to migrate away from Gaussian 09, using Gamess-US instead for molecular modelling of some heavy alkaline earth metal complexes, using density functional theory (DFT). In some of my previous Gaussian inputs I used the SDD (Stuttgart/Dresden) pseudopotential with the metallic cation ($$\ce{Sr^2+}$$). Now I intend to reproduce this calculation in Gamess-US.

After a couple of days figuring out how to use mixed basis sets in Gamess, I searched the Basis Set Exchange for this Stuttgart/Dresden ECP specification. Then I got confused, because there's no basis listed with that exact name. The closest I've found available for strontium was Stuttgart RLC and Stuttgart RSC 1997.

Which of these (if any) is the best match to the SDD pseudopotential available in Gaussian?

• Have you tried to look on their website? tc.uni-koeln.de/PP/clickpse.en.html In your shoes, I would try to compare the pseudo potentials from the Gaussian output file (I hope you still have access to it) and the pseudo potentials from that website.
– Pier
Mar 20, 2020 at 21:34