Toward spectroscopic accuracy for organic free radicals: Molecular structure, vibrational spectrum, and magnetic properties of F(2)NO.

The structure, harmonic frequencies, and hyperfine couplings of F(2)NO have been computed by the coupled cluster ansatz using a hierarchical series of basis sets and, in some cases, extrapolation procedures to reach the complete basis set limit. Methods rooted into the density functional theory have been used to estimate anharmonic and environmental effects. The remarkable agreement with experimental hyperfine coupling constants and most of vibrational frequencies confirms the reliability of the computational approach and suggests that one of the observed frequencies probably refers to a different species.