Near sulfur L-edge X-ray absorption spectra of methanethiol in isolation and adsorbed on a Au(111) surface: a theoretical study using the four-component static exchange approximation
2010 (English)In: PHYSICAL CHEMISTRY CHEMICAL PHYSICS, ISSN 1463-9076, Vol. 12, no 21, 5596-5604 p.Article in journal (Refereed) Published
The relativistic four-component static exchange approach for calculation of near-edge X-ray absorption spectra has been reviewed. Application of the method is made to the Au(111) interface and the adsorption of methanethiol by a study of the near sulfur L-edge spectrum. The binding energies of the sulfur 2p(1/2) and 2p(3/2) sublevels in methanethiol are determined to be split by 1.2 eV due to spin-orbit coupling, and the binding energy of the 2p(3/2) shell is lowered from 169.2 eV for the isolated system to 167.4 and 166.7-166.8 eV for methanethiol in mono-and di-coordinated adsorption sites, respectively (with reference to vacuum). In the near L-edge X-ray absorption fine structure spectrum only the sigma*(S-C) peak at 166 eV remains intact by surface adsorption, whereas transitions of predominantly Rydberg character are largely quenched in the surface spectra. The sigma*(S-H) peak of methanethiol is replaced by low-lying, isolated, sigma*(S-Au) peak(s), where the number of peaks in the latter category and their splittings are characteristic of the local bonding situation of the sulfur.
Place, publisher, year, edition, pages
Royal Society of Chemistry , 2010. Vol. 12, no 21, 5596-5604 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-56796DOI: 10.1039/b926109eISI: 000277926500010OAI: oai:DiVA.org:liu-56796DiVA: diva2:322266