XANES spectra of forsterite in crystal, surface, and amorphous states

The electronic structures of forsterite and its amorphous state were investigated using soft X-ray absorption near-edge structure (XANES) analysis at the Mg, Si, and O K-edges. The experimental spectra were reproduced theoretically using density functional theory calculations. Surface-sensitive XANES spectra for the (001), (010), and (100) surfaces were also observed. This study reports the first observation at the O K-edge using synchrotron radiation, and, in addition, reveals that the spectra is surface-sensitive at the Mg and Si K-edges. These findings demonstrate that XANES is a powerful technique to study silicate compounds.