Chemical order in liquid As2Se3 at high temperatures obtained by X-ray scattering and reverse Monte Carlo modeling

X-ray scattering experiments for liquid As2Se3 were carried out at high temperatures up to 1673 K at 6 MPa, using synchrotron radiation at SPring-8 in Japan, and the structure factor with reasonably nice statistics is obtained. The first peak position in the pair distribution function slightly shifts to smaller distance and the first minimum at 2.7 Å develops, as the metallic properties are enhanced with increasing temperatures. A first sharp diffraction peak at 1.2 Å− 1 in the structure factor becomes broad with an increasing temperature. The partial structure factors in liquid As2Se3 were deduced by Reverse Monte Carlo modeling constrained by partial coordination number fractions reported by the first principles molecular dynamics simulations. Chemical order correlated with the medium range order expected by the first sharp diffraction peak is discussed on the basis of results from the Reverse Monte Carlo modeling.