Correlation consistent basis sets for explicitly correlated wavefunctions: Pseudopotential based basis sets for the post-d main group elements Ga–Rn

New correlation consistent basis sets, cc-pVnZ-PP-F12 (n = D, T, Q), for all the post-d main group elements Ga–Rn have been optimized for use in explicitly correlated F12 calculations. The new sets, which include not only orbital basis sets but also the matching auxiliary sets required for density fitting both conventional and F12 integrals, are designed for correlation of valence sp, as well as the outer-core d electrons. The basis sets are constructed for use with the previously pub- lished small-core relativistic pseudopotentials of the Stuttgart-Cologne variety. Benchmark explic- itly correlated coupled-cluster singles and doubles with perturbative triples [CCSD(T)-F12b] cal- culations of the spectroscopic properties of numerous diatomic molecules involving 4p, 5p, and 6p elements have been carried out and compared to the analogous conventional CCSD(T) results. In general the F12 results obtained with a n-zeta F12 basis set were comparable to conventional aug- cc-pVxZ-PP or aug-cc-pwCVxZ-PP basis set calculations obtained with x = n + 1 or even x = n + 2. The new sets used in CCSD(T)-F12b calculations are particularly efficient at accurately re- covering the large correlation effects of the outer-core d electrons.