Abstract
Sulfur K-edge XANES has been measured for three sulfur model compounds, dibenzothiophene, dibenzothiophene sulfone, and aliphatic sulfur (DL-methionine). The spectra have been simulated with Density Functional Theory (DFT) by using a number of methods, including the half-core-hole approximation. Dipole transition elements were calculated and the transitions were convoluted with linearly increasing Gaussian functions in the first 20 eV of the near-edge region. In the case of dibenzothiophene, relaxation of the first excited states in the presence of the core-hole gave a further improvement. The theoretical results reproduce well the features of the spectra and give insight in the relation between geometric structure and molecular orbitals. Though DL-methionine and dibenzothiophene show a similar sharp rise of the white line, their molecular levels are quite different., pointing out the difficulties in finding useful "fingerprints" in the spectra for specific compounds.
Original language | English |
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Pages (from-to) | 2750-2756 |
Number of pages | 7 |
Journal | Journal of Physical Chemistry A |
Volume | 113 |
Issue number | 12 |
DOIs | |
Publication status | Published - 26 Mar 2009 |
Keywords
- X-ray-absorption
- Density-functional theory
- Fine-structure
- Core-hole
- Petroleum asphaltenes
- Electronic-structure
- Spectroscopy
- Speciation
- Energy
- Metal