Atomic ordering in Bi₄Ge₃O₁₂ melt by reverse Monte Carlo simulations

A three-dimensional structure model which well reproduces experimental structure functions for molten Bi₄Ge₃O₁₂ and agrees with the results of EXAFS experiments has been constructed by reverse Monte Carlo simulations. From the model atomic configuration the partial atomic distribution functions, the partial coordination number and distance of molten Bi₄Ge₃O₁₂ have extracted. It has been found that, on an atomic scale, molten Bi₄Ge₃O₁₂ may well be described as an assembly of disconnected GeO₄ tetrahedra dispersed in a medium of weakly correlated Bi and O atoms The structural differences between molten and crystalline Bi₄Ge₃O₁₂ have also been discussed in an attempt to clarify the reasons that make the process of pure Bi₄Ge₃O₁₂ crystals growth from the melt difficult.