文摘
The electronic properties of fluorosulfonyl isocyanate, FSO2NCO, were investigated by means of photoelectron spectroscopy and synchrotron based techniques. The first ionization potential occurs at 12.3 eV and was attributed to the ejection of electrons formally located at the 蟺 NCO molecular orbital (MO), with a contribution from nonbonding orbitals at the oxygen atoms of the SO2 group. The proposed interpretation of the photoelectron spectrum is consistent with related molecules reported previously and also with the prediction of OVGF (outer valence green function) and P3 (partial third order) calculations. The energy of the inner- and core鈥搒hell electrons was determined using X-ray absorption, measuring the total ion yield spectra, and the resonances before each ionization threshold were interpreted in terms of transitions to vacant molecular orbitals. The ionic fragmentation mechanisms in the valence energy region were studied using time-of-flight mass spectrometry as a function of the energy of the incident radiation. At 13 eV the M+ was the only ion detected in the photoion鈥損hotoelectron鈥揷oincidence spectrum, while the FSO2+ fragment, formed through the breaking of the S鈥揘 single bond, appears as the most intense fragment for energies higher than 15 eV. The photoion鈥損hotoion鈥損hotoelectron鈥揷oincidence spectra, taken at the inner- and core-levels energy regions, revealed several different fragmentation pathways, being the most important ones secondary decay after deferred charge separation mechanisms leading to the formation of the O+/S+ and C+/O+ pairs.