Universal R12 suited basis sets for atoms from lithium to fluorine

Abstract

Extended basis sets suitable for explicitly correlated R12 calculations have been constructed for the first row atoms from Li to F. These should have a fairly universal character, being defined as a compromise to describe atomic ground states and both the positive and negative ions. At the same time, the potential to create numerical instabilities is minimized. Energies with the final ‘universal' basis sets differ at the 10−5–10−6 E h level from the ‘R12 optimal' energies for individual systems and provide both very good ionization potentials and electron affinities.