TiCl, TiH, and TiH+ bond energies:: a test of a correlation-consistent Ti basis set

Correlation-consistent basis sets are developed for the Ti atom. The polarization functions are optimized for the average of the F-3 and F-5 states. One series of correlation-consistent basis sets is for 3d and 4s correlation, while the second series includes 3s and 3p correlation as well as 3d and 4s correlation. These basis sets are tested using the Ti F-3-F-5 separation and the dissociation energies of TiCl X(4)Phi, TiH X(4)Phi, and TiH+ X(3)Phi. The CCSD(T) complete basis set limit values are determined by extrapolation. The Douglas-Kroll approach is used to compute the scalar relativistic effect. Spin-orbit effects are taken from experiment and/or are computed at the CASSCF level. The Ti F-3-F-5 separation is in excellent agreement with experiment, while the TiCl, TiH, and TiH+ bond energies are in good agreement with experiment. Extrapolation with the valence basis set is consistent with other atoms, while including 3s and 3p correlation appears to make extrapolation more difficult.