As2Se3 is well known as a prototype material having a strong glass-forming tendencyand a semiconducting nature. The physical properties of non-crystalline As2Se3 havebeen intensively investigated from an experimental as well as theoretical point of view,see e.g. [1]. X-ray [2, 3] and neutron [4] diffraction as well as X-ray absorption spectroscopy [5, 6] showed that glassy (g-) and liquid (l-) As2Se3 have a short-range order(SRO) similar to the crystal, i.e., threefold coordinated As and twofold coordinated Seare covalently bonded to each other. The occurrence of a pre-peak around 1.2A±±1inthe total structure factor S(Q) in both g- and l-As2Se3measured by diffraction methodspresents evidence of intermediate-range order (IRO). However, the origin of the prepeak or the IRO is still open to discussion
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