The calculations of Ti K-edge X-ray absorption near-edge structures (XANES) in fresnoite Sr2TiSi2O8 are carried out using multiple-scattering method. The origins of the pre-edge peak along with the fine structures in the main peak of Ti K-edge XANES are interpreted by comparing the calculations in various modified structure models. It concludes that the pre-edge peak is dominantly determined by the structure (including both coordination and bond lengths) within the nearest-neighbor distance, while the fine structures beyond the pre-edge peak region are sensitively determined by the structure extending to the medium-range distance

We have proposed a new mixed approach by combining efficiently classical and first-principles molecular dynamics to study undercooling of liquid silicon, regardless of a specific empirical interaction model. Our results show an enhancement of the local tetrahedral ordering in the deep undercooled region associated to the appearance of propagating shear waves and give a strong support to the existence of a transition between a high density liquid to a low density liquid near 1050 K. An analysis of the structural, dynamics and electronic properties is proposed to elucidate these features.

Structure property function relationships provide valuable guidelines for a systematic development of functional materials. It is demonstrated how an augmented bond valence (BV) approach helps to establish such relationships in solid electrolytes. In principle it permits to identify mobile species, transport pathways and provides estimates for ion mobilities. In this work we discuss ion conduction pathways in glassy Lithium metasilicate as an illustrative example. The required representative local structure model is derived from Molecular Dynamics simulations, which provides the opportunity to compare the bond-valence-based predictions from a static structure model with a comprehensive analysis of a complete simulation trajectory. It is shown that understanding the bond valence mismatch as an effective Morse-type interaction opens up a way for systematically analyzing ion transport pathways and for a generally applicable method with improved reliability to predict ion transport characteristics in solid electrolytes from the structure model.

We have analyzed liquid structures of the binary Zr-TM (TM=Pd, Cu, Ni) alloys as a function of composition to investigate relations with their glass-forming abilities. High-energy x-ray (E=113 keV) diffraction experiments were performed and a conical nozzle levitation (CNL) technique was applied to achieve a containerless condition for highly reactive melts with high temperature. Structure information of the liquid alloys has been obtained with the aid of reverse Monte Carlo simulation. A shoulder was found at high-Q side of the second peak for the structure factor for Zr70Pd30 as well as the Zr70Cu30 alloy and the Zr50Cu50 alloys, which can be indication of the formation of ISRO in the liquid alloys. Liquid Zr-Ni alloys shows an apparent difference in the structure factors between the Zr70Ni30 and the Zr50Ni50 alloys, which can be associated with the formation of the chemical short range ordering, whereas the Zr-Pd alloys show a typical random distribution of atoms.