Knowledge Bank

We have carried out calculational and spectroscopic investigations of several fluorinated ethyl radicals. The first electronic spectrum of the $\alpha ,\alpha$-difluorethyl radical $(CF2CH3)$ was observed between 335 nm and 475 nm by resonance enhanced multiphoton ionization (REMPI) spectroscopy. The spectrum arises form two-photon resonances with a 3p Rydberg state. A third laser photon inonized the radicals. The electronic origin is tentatively assigned at $\nu 00=43275cm-1$ and the vibrational progression is assigned as the . In support of these spectral assignments we report {ab initio} calculations at the $MP2/6-31G\ast ,G1$, and G2 theory levels which found the optimum structures, vibrational frequencies, and relative energies of $CF2CH3,C2CH3+,CHF2CH2$, and $CHF2CH2\mathrm{<mrow\; data-mjx-texclass="ORD">+</mrow>}$. These results are also discussed in the context of similar work on the analogous fluoromethyl radical $(CF2H)$.