Assessment of a computational strategy approaching spectroscopic accuracy for structure, magnetic properties and vibrational frequencies of organic free radicals: the F(2)CN and F(2)BO case.

The molecular structure, vibrational frequencies, and hyperfine couplings of F(2)CN and F(2)BO have been computed at the coupled cluster level in conjunction with hierarchical series of correlation consistent basis sets. For geometrical and hyperfine parameters, extrapolation to the complete basis set limit and inclusion of core correlation effects have been considered. While a remarkable agreement with most of vibrational frequencies supports the reliability of the computational approach followed, experimental geometries cannot be used for validation purposes due to their limited accuracy. In view of previous experience with related radicals, the computed hyperfine coupling constants as well as molecular structures are expected to be very reliable and accurate.