Laser-induced fluorescence of the CD2CFO radical

The laser-induced fluorescence spectrum of the (B) over tilde (2)A"-->(X) o ver tilde (2)A" transition of the CD2CFO radical has been observed in the r egion 316-335 nm. The radical was produced by 193 nm photolysis or by fluor ine atom reaction with acetyl-d(3) fluoride. The spectrum of CD2CFO was sim ilar to that of CH2CFO reported previously except for small isotope shifts in the range 7-343 cm(-1). The isotope shifts support the assignment of the se spectra to fluorinated vinoxy radicals, and rule out the alternate assig nment to FCO proposed by others. The (X) over tilde -->(B) over tilde elect ronic transition energy (T-0) for CD2CFO was measured to be 29 867 cm(-1), which is only 7 cm(-1) lower than that for CH2CFO. From an analysis of the laser-induced single vibronic level fluorescence, some of the vibrational f requencies can be assigned for the ground electronic state; nu(3)(CO str.)= 1735; nu(4)(CD2 sciss.)=1043; nu(5)(CF str.)=1248; nu(6)(CD2 rock.)=774; nu (7)(CC str.)=863; nu(8)(CCF bend)=597; and nu(9)(CCO bend)=370 cm(-1). For the (B) over tilde (2)A" state, nu(3)=1772; nu(4)=1073; nu(5)=1241; nu(6)=7 83; nu(7)=827; nu(8)=530; and nu(9)=370 cm(-1). These assignments are suppo rted by ab initio calculations. Among these fundamental frequencies, the nu (4) and nu(6) modes showed the largest isotope shifts, although isotope eff ects were observed in all the above vibrational fundamentals. The radiative lifetimes of the excited CD2CFO and the quantum yield of formation of the CH2CFO radical from photolysis of CH3CFO at 193 nm are also reported. (C) 1 999 American Institute of Physics. [S0021-9606(99)02238-2].