The pure rotational spectrum and hyperfine structure of CF studied by laser magnetic resonance

Laser magnetic resonance spectra have been measured for four rotational transitions and one spin-changing transition in the 2Π ground state of CF, generated in an intracavity methane–fluorine flame. From a detailed analysis of the Zeeman hyperfine structure of the J = 9/2→11/2 transition in the Ω = 3/2 spin component the hyperfine constants h, b, and d as well as B0 and q0 have been determined. Using these fitted parameters in conjunction with ab initio results, the values of 〈1/r3〉, 〈(3 cos2ϑ−1)/r3〉, ‖ψ2(0)‖, and 〈(sin2ϑ)/r3〉, averaged over the unpaired electron distribution, have been determined. Comparison of these integrals with those of the fluorine atom indicates that the unpaired electron has approximately 18% F character, implying a substantial degree of double bonding.