Calculation of hyperfine coupling constants of the CN and CP ground state radicals

By carrying out a systematic basis set and electron correlation investigation, we have determined accurately the hyperfine coupling constants of the ground states of CN and CP. The basis set studies began with Dunning’s correlation consistent bases, after which systematic uncontractions and extensions with diffuse and tight functions were introduced until saturation was achieved. The basis set self-consistent-field (SCF) wave function results compare favorably with numerical Hartree–Fock (HF) results. The electron correlation study was based on extending systematically the active space of a complete valence orbital spin-restricted multiconfiguration self-consistent-field (MCSCF) wave function and using the MCSCF restricted–unrestricted response function approach to obtain the hyperfine coupling constants.