The microwave spectrum of the difluorocyanomethyl radical, ĊF2CN

Lu Kang, Kennesaw State University
Ha Vinh Lam Nguyen, Université Paris-Est Créteil
Christopher B. Falls, Wesleyan University Middletown
Alexander B. Seys, Wesleyan University Middletown


The pure rotational spectrum of the open shell difluorocyanomethyl radical, ĊF2CN, has been measured using two Balle-Flygare-type cavity Fourier-Transform-Microwave (FTMW) spectrometers both equipped with pulsed discharge nozzles. A total of 156 transitions (from N = 1 – 0 to 6 – 5, and Ka = 0, 1, 2, 3) in the electronic ground state were observed between 6.5 GHz and 38.4 GHz with a typical linewidth of ∼5 kHz full-width-half-maximum. A Hamiltonian that included semi-rigid rotor, spin-rotation, and nuclear hyperfine parameters was fit to the observed data set and these parameters have been interpreted and compared to similar radicals. Excellent agreement between experimental and uB3LYP/aug-cc-pVQZ calculated rotational constants, the experimental inertial defect, −0.6858(2) uÅ2, and the failure of a coupling scheme in which the fluorine nuclei are treated as identical and related by a C2v symmetry axis combine to indicate a nonplanar structure for the ĊF2CN radical.