The Si L2,3 X-ray absorption near-edge structure (XANES) can be used to probe thelocal structure around Si and derive electronic information of the unoccupied s- andd-like partial density of states in nano-size SiO2. We present Si L2,3-edge for threedifferent size silicates acquired by total electron yield (TEY) at the photoemission sta-tion of Beijing Synchrotron Radiation Facility (BSRF). The Si L2,3-edge spectra areinterpreted based on ab initio full multiple-scattering (MS) calculation. The Si L2.3-edge of nano-size materials has XANES similar to that of a-quartz. The similaritiesbetween the Si L2.3-edge shapes attest to a common molecular-orbital picture of theirSi-O bonding and the same coordination state. However, a considerable broadeningof Si L2,3-edge XANES spectra as decrease of particle size is also an indicative ofpolyhedral distortions.
Z.Y. Wu, K. Ibrahim, G. Li, J. Zhang, F.Q. Liu, M.I Abbas, R. Hu, H.J. Qian and F.Q. Tang ( Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, The Chinese Academy of Sciences, Beijing 100039, China) ( Laboratori Nazionali di Frascat
Photoemission behaviors of nano-CeO2 films with particle sizes ranging from 8 nm to 50 nm and bulk CeO2 in Ce 4 d-4 f absorption region have been investigated. Resonant enhancements of Ce 4 f valance band and Ce 5 p bands for nano film and bulk material have been observed. The variation of electron density of states in valance bands of nano and bulk structures of CeO2 is discussed in terms of Ce 4 d-4 f resonance.
M.I. Abbas, K. Ibrahim, Z.Y. Wu, J. Zhang, F.Q. Liu and H.J. Qian (Beijing Synchrotron Radiation Laboratory, Institute of High Energy Physics, The Chinese Academy of Sciences, P.O. Box 918, Beijing 100039, China)
