Correlated, relativistic, and basis set limit molecular polarizability calculations to evaluate an augmented effective core potential basis set

initial investigations have demonstrated that an augmented ECP basis set can be used to calculate valence electronic properties with deviations of less than 1% from all-electron basis sets. Past work has largely focused on molecules with relatively light atoms (Z < 18) examined with time-dependent Hartree-Fock (TDHF) theory. In this work, the dipole moment and polarizability of a number of well-studied molecules are examined with HF, MP2, CCSD, and CCSD(T) correlated wave functions. Additionally, systems not as thoroughly studied due to the difficulty of all-electron calculations when Z = 50-85 are included. The SBK ECP basis set, augmented with optimized valence functions, performs well across a broad range of methods, less than 3% different from all electron relativistic and correlated wave functions. Orders of magnitude time savings (10(1)-10(4)) are exchanged for a minimal difference from all-electron basis sets. (c) 2006 Wiley Periodicals, Inc.