A determination of the structure of liquid using neutron diffraction and isotopic substitution

Abstract

The partial structure factors and pair distribution functions for liquid were measured using the method of neutron scattering and isotopic substitution. The results show many features which are consistent with an ionic melt in which small ions move rapidly through a highly ordered liquid sub-structure in a similar way to the motion of in the fast-ion solid which exists prior to melting. The results are compared with recent molecular dynamics and ab initio molecular dynamics calculations, and the relative merits of the two simulation approaches are discussed in relation to the data.

Concentration Effects of Silver Ions on Forming Cooperative Conduction Path in Superionic Melts

“…4) The position of the first peak in the S(Q) for molten Ag 2 Se, observed at Q = 2.77 Å -1 , is in good agreement with those obtained by neutron diffraction measurements 12) and by an ab initio MD simulation.…”

Structure of Ba-Ti-Al-O glasses produced by aerodynamic levitation and laser heating

“…The total amount of the sample in the neutron beam was estimated from the density of the glass and the packing density of the spheres in the container (as measured by the total height of the spheres). The experimental data were corrected for self-absorption, multiple scattering and container scattering [40]. The sample scattering was put on an absolute scale by reference to a standard vanadium bar of 6.072(6) mm placed at the sample position.…”

Dual Chemical Role of Ag as an Additive in Chalcogenide Glasses

“…a-Ag 2 Se crystallizes [15] in a body-centered cubic lattice of Se atoms in which four Ag 1 ions rapidly diffuse through tetrahedral interstitial sites. Rapid diffusion occurs because of a delicate balance [16] between ionic and covalent interactions that drive the free energy difference ͑E 6 -E 4 ͒ between Ag coordination numbers (CN) of 6 and 4 to vanish.…”

“…Rapid diffusion occurs because of a delicate balance [16] between ionic and covalent interactions that drive the free energy difference ͑E 6 -E 4 ͒ between Ag coordination numbers (CN) of 6 and 4 to vanish. Topologically, the structure of a-Ag 2 Se bears a similarity to that of its melt, as revealed by neutron structure factors [15], and may be used to model the glass as well. The consequence of E 6 !…”