Polarized XANES spectroscopy: the K-edge of layered K-rich silicates.

Angle-resolved XANES spectra have been collected at the potassium K-edge using polarized synchrotron radiation on several natural mica crystals. Experimental data have been interpreted on the basis of the MS theory and, within this theoretical framework, the edge of this low-Z atom is de-composed so as to produce two partial patterns giving, respectively, the full in-plane absorption spectrum and the full out-of-plane one. The method here described is appropriate to describe the X-ray dichroic behavior of solid layered compounds and/or two-dimensionally extended structures.