title: Functional groups and sulfur K-edge XANES spectra: divalent sulfur and disulfides.
abstract: Sulfur K-edge XANES was measured for two divalent sulfurs (dibenzyl and benzyl phenyl) and two disulfides (dibenzyl and diphenyl). The absorption spectra could be assigned using density functional theory with the "half core hole" approximation for the core hole including relaxation of selected excited states at the absorption edge. Analysis of the molecular orbitals shows that the characteristic double peak of the dibenzyl disulfide arises as a consequence of the enhanced splitting of the LUMO (lowest unoccupied molecular orbital) and the LUMO + 1. Exchange of the ligand benzyl by phenyl introduces more transitions at the absorption edge, which enhance the broadening in the divalent sulfur and splitting of the peaks of the disulfide. It is shown that different ligand groups introduce significant differences in the absorption edge, which poses a problem for the speciation analysis when the ligand groups are not clearly defined.
authors: Inorganic Chemistry and Catalysis group, Department of Chemistry, Utrecht University, Sorbonnelaan 16, 3584 CA, Utrecht, The Netherlands. Ana.Mijovilovich@lightsource.ca
authors: Ana
authors: A
authors: Mijovilovich
authors: Lars G M
authors: LG
authors: Pettersson
authors: Frank M F
authors: FM
authors: de Groot
authors: Bert M
authors: BM
authors: Weckhuysen
mesh_terms: D001593:Benzyl Compounds / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011789:Quantum Theory; D013057:Spectrum Analysis; D013440:Sulfides / Q000737:chemistry*; D014965:X-Rays
chemical_list: D001593:Benzyl Compounds; D004220:Disulfides; D013440:Sulfides; C053871:diphenyl disulfide; C492349:dibenzyl disulfide; C016367:benzyl sulfide