No abstract

No abstract

A high-performance double-crystal-monochromator soft X-ray (DCMSX) beamline has been constructed at the Synchrotron Radiation Research Center (SRRC). This beamline delivers monochromatic photon beams with energies from 1 to 9 keV and a resolving power (E/DeltaE) of up to 7000. This beamline provides users with an opportunity to study many important materials, such as high-T(c) superconductors, magnetic materials, catalysts, super-alloy compounds etc. Excellent EXAFS and NEXFS spectra have been routinely obtained from this beamline. Several interesting research projects are currently being conducted at this beamline. All the results show that this beamline has been constructed to meet its design goals.

No abstract

This study measures the x-ray-absorption spectra of a crystalline ͑c͒-Si-C-N thin film at the C and Si K edge using the sample drain current mode and at the N K edge using the fluorescence mode. A resonance peak resembling the C 1s core exciton in the chemical-vapor-deposition-diamond/Si is observed. In addition, a broad feature is found in the energy range between ϳ290 and 305 eV, which can be assigned to the antibonding C 2p-Si 3sp hybridized states and the C 2p-N 2sp hybridized states as well. The fact that the resonance peak is located ϳ1.5 eV below the C 1s ionization energy suggests that the Frenkel-type exciton model can appropriately describe the core exciton of carbon atoms in c-Si-C-N. Closely examining the N K edge near edge absorption spectra reveals similar features in both c-Si-C-N and ␣-Si 3 N 4 , indicating that nitrogen atoms generally have a similar local environment in these two materials. Moreover, results obtained from Si K-edge absorption spectra of c-Si-C-N demonstrate a proportional combination of local Si-N and Si-C bonds associated with the local tetrahedral C-Si-N 3 arrangement as well as the long-range ordered atomic structure around Si atoms. Theoretical calculations using the first-principles pseudofunction method are also presented and compared with experimental data. ͓S0163-1829͑98͒08037-0͔