Valence and correlating basis sets for the second transition-metal atoms from Y to Cd

Contracted Gaussian-type function sets are developed for the valence 5s and 4d orbitals and for correlating functions of the second transition-metal atoms Y through Cd. A segmented contraction scheme is used for its compactness and efficiency. Contraction coefficients and exponents are determined by minimizing the deviation of the target function from the average of accurate atomic natural orbitals for the three lowest LS states arising from the 5s(2) 4d(n-2), 5s(1) 4d(n-1), and 5s(0) d(n) configurations. The present basis sets give a well balanced description for the three configurations at the Hartree-Fock level, and yield more than 97% of the atomic correlation energies predicted by accurate natural orbitals of the same size.