NiO nanocrystals with the average size of 5, 10 and 25 nm were synthesized by gas-condensation method. The energy positions of the continuum resonances are discussed on the basis of an empirical bond-length correlation supporting a 1/ r2 - dependence.įundamental absorption edge of NiO nanocrystals The corresponding values correlate with the valence of the cations and the intensity of the white lines. We discuss the energy differences between the white line positions and the corresponding P ls binding energies as a measure of half of the energy gap. The measured spectra demonstrate that chemical changes beyond the PO 4- tetrahedra are reflected by energy shifts of the pre- edge and continuum resonances, by the presence of characteristic shoulders and new peaks and by differences in the intensity of the white line. The X-ray absorption near edge structure (XANES) at the P K- edge in several orthophosphates with various cations, in condensed, and in substituted sodium phosphates have been measured using synchrotron radiation from the ELSA storage ring at the University of Bonn.
The P K-near edge absorption spectra of phosphates
Good agreement between experimental results and published data is obtained. The measured values were compared with the published data. The experimental work has been performed at Beijing Synchrotron Radiation Facility.
Details of experimental methods and results are given and discussed. The investigation confirmed that XANES is useful technique for multi-element absorption coefficient measurement. Our results showed a wide range of data, the total measured data of mass- absorption coefficient of the seven elements was about 505. So that, there are only a few points mass- absorption coefficient at the near edge absorption and that always average value in published table. It is well known that, on the near edge absorption of element, when incident X-ray a few eV change can make the absorption coefficient an order magnitude alteration. X-ray absorption near edge structure (XANES) was used to study the near edge mass- absorption coefficients of seven elements, such as, Ti, V, Fe, Co, Ni, Cu and Zn. Studies on absorption coefficient near edge of multi elementsĮisa, M.
0 kommentar(er)
