New correlation consistent-like basis sets have been developed for the post-d group 13–15 elements ~Ga–As, In–Sb, Tl–Bi! employing accurate, small-core relativistic pseudopotentials. The resulting basis sets, which are denoted cc-pVnZ-PP, are appropriate for valence electron correlation and range in size from (8s7p7d)/@4s3p2d# for the cc-pVDZ-PP to (16s13p12d3 f 2g1h)/ @7s7p5d3 f 2g1h# for the ...