Vacuum ultraviolet photoelectron spectroscopy of transient species. Part 18.—The cyclopropyl, isopropyl and n-propyl radicals

A kinetics and mechanistic study of the atmospherically relevant reaction between molecular chlorine and dimethyl sulfide (DMS)

“…However, apart from the reactants and products, nine other minimum energy structures were located on the potential surface (see Figure 7), most notably a reaction intermediate (CH 3 ) 2 SCl 2 (see Figure 8). In separate experiments (5), it was found that the photoelectron spectrum obtained for a reaction intermediate from reaction (1), bands at 9.69 and 10.62 eV in Figure 2 are part of this spectrum, could not be assigned to reactant or product-type intermediates, DMS:Cl 2 or CH 3 SCH 2 Cl:HCl, but could be assigned to (CH 3 ) 2 SCl 2. There is also infrared evidence to support this conclusion (5 Figure 8 and the computed structures of the transition states are shown in Figure 9.…”

“…It has the potential to observe reactants, intermediates and products and to measure branching ratios between reaction channels which give different intermediates and/or final products. An example of a reaction studied by PES in Southampton in which different intermediates were observed is the reaction between F atoms and propane which gives rise to the n-propyl and iso-propyl radicals as primary products (1). The only previous use of PES in a kinetics study is the work of Wang et al, who studied the unimolecular thermal rearrangements of a number of compounds (2-4), notably isomerisation of CH 3 NC to CH 3 CN (2) and isomerisation of SSF 2 to FSSF (3).…”

“…The reaction studied in this work is the atmospherically important reaction between molecular chlorine and dimethyl sulfide (DMS) Cl 2 + CH 3 SCH 3 → products ----- (1) This work, as well as related research with photoelectron, infrared and ultraviolet/visible spectroscopy and ab initio molecular orbital calculations (5), has shown that this reaction proceeds via a covalently bound intermediate, (CH 3 ) 2 SCl 2 , and to give CH 3 SCH 2 Cl and HCl as the products. The sulfur cycle in the earth's atmosphere has been the subject of intensive investigation in recent years because of the need to assess the contribution of anthropogenically produced sulfur to acid rain, visibility reduction and climate modification.…”

A study of the BrO and BrO2 radicals with vacuum ultraviolet photoelectron spectroscopy

“…22 Under typical operating conditions, the resolution as measured from the full width at half maximum ͑FWHM͒ of the Ar ϩ ( 2 P 3/2 )←Ar( 1 S 0 )(3p) Ϫ1 photoelectron band was approximately 30 meV. Spectra were obtained by linearly sweeping the pass energy of an electrostatic hemispherical analyzer.…”

The X̃ 2B1, B22, A12, and A22 states of oxygen difluoride cation (F2O+): High-level ab initio calculations and simulation of the ultraviolet photoelectron spectrum of F2O

“…51 Briefly, it consists of a 150°sector hemispherical analyzer, a differentially pumped ionization chamber, a capillary He discharge light source and a channeltron detector. The operational resolution is better than 30 meV FWHM for Ar.…”