What accuracy do the basis sets give?

Tests on many diatomics were performed by Dr. E. van Lenthe to test the various basis sets. We now document the results of some of these tests, in order to give a feeling for the quality that can be obtained from the various basis sets. See also: E. van Lenthe, E.J. Baerends, Optimized Slater-type basis sets for the elements 1-118, J. Comp. Chem. 24 (2003) 1142-1156.