High-resolution X-ray pair distribution functions for molten and glassy TeO2 reveal coordination numbers nTeO ≈ 4. However, distinct from the known α-, β-, and γ-TeO2 polymorphs, there is considerable short-range disorder such that no clear cutoff distance between bonded and nonbonded interactions exists. We suggest that this is similar to disorder in δ-TeO2 and arises from a broad distribution of asymmetric Te-O-Te bridges, something that we observe becomes increasingly asymmetric with increasing liquid temperature. Such behavior is qualitatively consistent with existing interpretations of Raman scattering spectra, and equivalent to temperature-induced coordination number reduction, for sufficiently large cutoff radii. Therefore, TeO2 contains a distribution of local environments that are, furthermore, temperature dependent, making it distinct from the canonical single-oxide glass formers. Our results are in good agreement with high-level ab initio cluster calculations.

中文翻译：

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TeO2熔融和玻璃中的短程失调。

熔融和玻璃态TeO2的高分辨率X射线对分布函数揭示了配位数nTeO≈4。但是，与已知的α-，β-和γ-TeO2多晶型物不同，存在相当大的短程无序现象，因此不清楚存在键合和非键合相互作用之间的截止距离。我们建议，这类似于δ-TeO2的无序，并且是由于不对称的Te-O-Te桥的广泛分布引起的，随着液体温度的升高，我们观察到的事情变得越来越不对称。对于足够大的截止半径，这种行为与拉曼散射光谱的现有解释在质量上是一致的，并且等同于温度引起的配位数的减少。因此，TeO2包含与温度有关的局部环境分布，使其与规范的单氧化物玻璃形成剂不同。我们的结果与高级从头算起簇计算非常吻合。