ANGULAR DEPENDENT XAFS STUDIES OF A MOSI2 SINGLE-CRYSTAL

We report angular dependent X-ray absorption measurements at the Mo L- 3,L-2 edge and the Si K-edge for a MoSi2 single crystal. The crystal w as oriented so that an azimuthal rotation of the cn stal about the sur face normal (direction of the incident photons) would align the c-axis of the crystal anywhere between parallel and perpendicular to the pol arization of the photons. It was found that while the Mo L-3,L-2 edge XANES shows little angular dependence, the Si K-edge XANES shows a ver y strong polarization dependence of which the intensity exhibits a two -fold symmetry. This angular dependence of the Si K-edge XANES is attr ibuted to the high densities of unoccupied states localized perpendicu lar to the Si-Si bond.