The correlation consistent basis sets are popular in high-accuracy electronic structure calculations, partly because of their regular energy convergence characteristics. We have recently designed, developed and tested correlation consistent basis sets for the heavy alkali (K–Fr) and alkaline earth (Ca–Ra) elements. This includes basis sets paired to specific pseudopotentials, and those for use with scalar relativistic Douglas-Kroll-Hess or eXact-2-Component Hamiltonians. We show that, perhaps unsurprisingly, the s and p outer core electrons should be correlated using a basis set designed for this purpose.
The basis sets can be downloaded in a variety of formats from ccRepo.
Gaussian basis sets for use in correlated molecular calculations. XI. Pseudopotential-based and all-electron relativistic basis sets for alkali metal (K–Fr) and alkaline earth (Ca–Ra) elements. J. G. Hill and K.A. Peterson, J. Chem. Phys., 2017, 147, 244106.