Dataset for "Structure of As-Se glasses by neutron diffraction with isotope substitution"

Data sets used to prepare Figures 1-7 in the Journal of Chemical Physics article entitled "Structure of As-Se glasses by neutron diffraction with isotope substitution." The data sets refer to the measured or modelled structure of As-Se glasses with compositions at or near to As_{0.30}Se_{0.70}, As_{0.35}Se_{0.65} and As_{0.40}Se_{0.60}.

Figure 1 shows the total structure factors F(k) for as-prepared glassy (a) As_{0.30}Se_{0.70}, (b) As_{0.35}Se_{0.65} and (c) As_{0.40}Se_{0.60}. The points with vertical error bars show the measured functions and the solid curves show spline fits. The error bars are smaller than the line thickness at most k values. The GEM data sets extend to k_{max} = 40 A^{-1} but are shown over a smaller k-range for clarity of presentation. In (c) a comparison is made between the ^{nat}F(k) functions measured using D4c (black curve) versus GEM (red curve).

Figure 2 shows the total pair-distribution functions G(r) for glassy (a) As_{0.30}Se_{0.70}, (b) As_{0.35}Se_{0.65} and (c) As_{0.40}Se_{0.60}. The broken curves show the Fourier transforms of the spline-fitted F(k) functions shown in Fig. 1. The solid curves show the same functions after the low-r oscillations have been set to the G(0) limit and the GEM data beyond the first peak have been smoothed by Fourier transforming F(k) after the application of a Lorch modification function with k_{max} = 40 A^{-1}. In (c) a comparison is made between the ^{nat}G(r) functions measured using D4c (black curves) versus GEM (red curves).

Figure 3 shows the difference functions Delta F_{gamma}(k) for glassy (a) As_{0.30}Se_{0.70}, (b) As_{0.35}Se_{0.65} and (c) As_{0.40}Se_{0.60}. The points with vertical error bars show the measured functions and the solid curves show the back Fourier transforms of the Delta G_{gamma}(r) functions given by the solid curves in Fig. 4. The error bars are smaller than the line thickness at most k values.

Figure 4 shows the difference functions Delta G_{gamma}(r) for glassy (a) As_{0.30}Se_{0.70}, (b) As_{0.35}Se_{0.65} and (c) As_{0.40}Se_{0.60}. The broken curves show the Fourier transforms of the spline-fitted Delta F_{gamma}(k) functions shown in Fig. 3. The solid curves show the same functions after the low-r oscillations have been set to the Delta G_{gamma}(0) limit and the data beyond the first peak have been smoothed by Fourier transforming Delta F_{gamma}(k) after the application of a Lorch modification function with k_{max} = 30 A^{-1} (GEM) or 23.45 A^{-1} (D4c).

Figure 5 shows a comparison between the difference functions (a) Delta F_{Se}(k), (b) Delta F_X(k) and (c) Delta F_{As}(k) obtained from FPMD (solid red curves), AXS-RMC (broken blue curves) and neutron diffraction (solid black curves). In the AXS-RMC work, the difference functions do not extend beyond k_{max} = 11.4 A^{-1}, and the curves labelled As_{0.30}Se_{0.70} and As_{0.35}Se_{0.66} correspond to actual compositions of As_{0.29}Se_{0.71} and As_{0.33}Se_{0.67}, respectively. Several of the curves have been offset vertically for clarity of presentation and the magnitude of the offset is indicated in parenthesis.

Figure 6 shows a comparison between the difference functions (a) Delta G_{Se}(r), (b) Delta G_X(r) and (c) Delta G_{As}(r) obtained from FPMD (solid red curves), AXS-RMC (broken blue curves) and neutron diffraction. In the AXS-RMC work, the curves labelled As_{0.30}Se_{0.70} and As_{0.35}Se_{0.66} correspond to actual compositions of As_{0.29}Se_{0.71} and As_{0.33}Se_{0.67}, respectively. Several of the curves have been offset vertically for clarity of presentation and the magnitude of the offset is indicated in parenthesis.

Figure 7 shows differences between the measured coordination numbers bar{n} or bar{n}_{gamma} and those calculated using the CON (black markers) and RCN (red markers) models for glassy As_{0.30}Se_{0.70} (squares), As_{0.35}Se_{0.65} (circles) and As_{0.40}Se_{0.60} (triangles). The bar{n} values for the samples containing ^{nat}Se and ^{76}Se are denoted by bar{n}_{nat} and bar{n}_{76}, respectively, and are highlighted in yellow and blue, respectively. The bar{n}_{Se}, bar{n}_X and bar{n}_{As}$ values are highlighted in green, cyan and magenta, respectively.