Polarization consistent basis sets, optimized for density functional calculations, are proposed for the elements Si-Cl. Their performance for atomization energies, equilibrium geometries, harmonic vibrational frequencies, and associated infrared intensities is compared with other commonly used basis sets. Atomization energies can be predicted to within 0.01 kJ/mol per atom of the basis set limit by extrapolation of the pc-2, -3, and -4 results. Equilibrium bond distances and harmonic vibrational frequencies can be calculated to within 10(-5) Angstrom and 0.5 cm(-1), respectively, of the basis set limit. The pc-n basis sets are shown to give comparable or better accuracy than other alternatives, while containing fewer or equal number of primitive basis functions. (C) 2004 American Institute of Physics.