Systematically Convergent Basis Sets for the f Block

The additional functions for the ( +2)p were optimized on the configuration in which the two ( +2)s electrons were replaced by two ( +2)p electrons. In addition to optimizing the exponents for this orbital, the exponents for the outermost antinode of the ( +1 )p were reoptimized, which allows some inward relaxation of the exponents for this antinode. The result is that the outermost maximum of the (n+2)s and p and the (n+l)s and p are represented by N functions for an NZ basis set that is, in a QZ basis set there are four functions whose coefficients are of comparable magnitude and of the same sign representing the outermost maximum of these shells. 

Correlating functions for the nd, f, ( +l)s and p, ( +l)d, and ( +2)s shells were optimized in MR-SDCI calculations. The ground state was used for the reference configuration for the nd, nf, (n-nl)s and p shells for the (n+1 )d and (n-n2)s shells, the nf (n-nl)d n+2)s configuration was used for the reference. The correlating sets were chosen so that the double zeta basis sets had one function with one unit higher angular momentum than the shell 

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