IR and UV absorption spectrum of the trifluoromethoxy radical, CF3O centerdot, isolated in rare gas matrices

The trifluoromethoxy radical is prepared in high yields by vacuum flash pyr olysis of CF3OC(O)OOC(O)-OCF3 or CF3OC(O)OOCF3 highly diluted in inert gase s, and subsequently isolated in inert gas matrices by quenching the product mixture at low temperatures. In the IR spectrum, six fundamentals have bee n observed and C-s symmetry is concluded for the matrix-isolated CF3O. radi cal by comparison with predicted band positions and band intensities from a b initio calculations. This finding is at variance with results from the an alysis of the rotational resolved fluorescence excitation spectra and dispe rsed fluorescence spectra of gaseous CF3O. radicals, where C-3 nu symmetry was found. Possible explanations for this discrepancy are given. The UV spe ctrum in the spectral region 28000-43000 cm(-1) has been measured for the f irst time, and two different electronic transitions are observed. The struc ture of the low energy transition (A) over tilde (2)A(1) <-- (X) over tilde E-2 is in agreement with that in previous laser induced fluorescence spect ra. Four vibrational progressions are found in the spectral range between t he band origin at 28517 cm(-1) and up to 32400 cm(-1). The spectroscopic re sults are compared with the gas phase and ab initio computed values and are discussed in detail.