Publications in Scientific Journals:
O. Diwald, M. Sterrer, E. Knözinger, P. Sushko, A. Shluger:
"Wavelength selective excitation of surface anions on highly dispersed MgO";
Journal of Chemical Physics,
116
(2002),
1707
- 1712.
English abstract:
Monochromatic UV light in the spectral interval between 4.0 and 5.5 eV is used in order to selectively excite 3- and 4-coordinated oxygen ion sites on the surface of MgO nanoparticles exposed to O2 gas. As a result, two different paramagnetic O- surface species and also ozonide anions O3- are observed by Electron Paramagnetic Resonance (EPR) spectroscopy. The relative abundance of each of the O- species exhibits a specific dependence on the energy of the exciting
photons. EPR data together with the results of theoretical modeling suggest that both O- species are located at 3-coordinated sites having different local environments. At sufficiently high O2 pressures molecular oxygen does not only act as an electron trap, favoring the O- formation, but it also contributes to UV induced O3- formation with a maximum efficiency at 4.2 eV.
Electronic version of the publication:
http://ojps.aip.org/getpdf/servlet/GetPDFServlet?filetype=pdf&id=JCPSA6000116000004001707000001&idtype=cvips
Created from the Publication Database of the Vienna University of Technology.