ELECTRONIC-SPECTRUM OF THE ALPHA,ALPHA-DIFLUOROETHYL RADICAL

The first electronic spectrum of the alpha,alpha-difluoroethyl radical (CF2CH3) was observed between 335 and 475 nm by resonance-enhanced mu ltiphoton ionization (REMPI) spectroscopy. The spectrum arises from tw o-photon resonances with a 3p Rydberg state. A third laser photon ioni zed the radicals. The electronic origin is tentatively assigned at nu( 00) = 43 275 cm(-1), and the vibrational progression is assigned as th e nu(9)'(CF2 wag) = 530 cm(-1). In support of these spectral assignmen ts, we report ab initio calculations at the MP2/6-31G, G1, and G2 the ory levels which found the optimum structures, vibrational frequencies , and relative energies of CF2CH3, CF2CH3+, CHF2CH2, and CHF2CH2+.