Primary products of the reactions of fluorine atoms with CH3OH, CH3SH and CH3OCH3 studied with ultraviolet photoelectron spectroscopy

Abstract

Abstract He I photoelectron spectra have been recorded for the reactions F+CH 3 OH, F+CH 3 SH and F+CH 3 OCH 3 and bands associated with the primary reaction products are identified. The known first photoelectron band of CH 2 OH, with an adiabatic ionization energy (IE) of (7.56±0.01) eV, and a sharp band with an adiabatic IE of (10.72±0.01) eV have been observed early in the F+CH 3 OH reaction. This latter feature is assigned to the first photoelectron band of CH 3 O. The corresponding band of CD 3 O has been observed in the F+CD 3 OH and F+CD 3 OD reactions and is found to be unchanged in shape and position from the first band of CH 3 O. Similarly, the first photoelectron bands of CH 3 S and CH 2 SH have been identified in spectra recorded for the F+CH 3 SH reaction. The CH 3 S first photoelectron band is sharp and has an adiabatic IE of (9.25±0.02) eV whereas the CH 2 SH first band is broad and has an adiabatic IE of (7.52±0.03) eV. These values are in excellent agreement with ionization energies obtained from recent photoionization mass spectrometric studies and molecular orbital calculations on these short-lived molecules. In addition, a broad band observed at low reaction times in the F+CH 3 OCH 3 reaction, with an adiabatic IE of (7.04±0.02) eV, is assigned to the first ionization of the CH 2 OCH 3 radical. The first band of the CD 2 OCD 3 isotopomer has also been identified in the corresponding F+CD 3 OCD 3 reaction. A comparison is made with the results obtained for the F+CH 3 SCH 3 reaction in which the first photoelectron band of CH 2 SCH 3 was recorded.