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<p>The PbO–SiO<sub>2</sub> system has a wide range of industrial applications, including optical glasses, optoelectronics, and radiation shielding. In this study, the structure of lead-silicate glasses was investigated using molecular dynamics (MD) simulations with Buckingham-type rigid ion potentials combined with Coulomb interactions. Three glass compositions, xPbO–(100 − x)SiO<sub>2</sub> with x = 50, 60, and 65&#xa0;mol%, were examined. In the simulated structures, Si<sup>4+</sup> ions are tetrahedrally coordinated with oxygen atoms, with an average coordination number of four. The PbO<sub>4</sub> units serve as the fundamental structural motifs in lead-silicate glasses. The number of Pb–Pb nearest neighbors follows a statistical model in which modifier cations (Pb<sup>2+</sup>) bond to non-bridging oxygens (Onb), and M(Onb)<sub>n</sub> polyhedra are primarily connected via corner-sharing. The Pb–Pb partial pair distribution function, T<sub>PbPb(r)</sub>, exhibits a peak height that increases with PbO concentration, as expected. The distribution of Q<sup>n</sup> species varies systematically with silica content, reflecting the depolymerization of the silicate network upon the addition of lead oxide. All structural models demonstrate good agreement with experimental data and Reverse Monte Carlo (RMC) modeling results, including parameters such as short-range order, average bond lengths, bond angle distributions, and Q<sup>n</sup> species distributions.</p>

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The short and medium range structure of lead silicate glasses

  • 期刊论文

  • 发表日期：

    2025年7月5日

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  • Bushra M ALHasni,
  • E. M. Ahmed

摘要

The PbO–SiO2 system has a wide range of industrial applications, including optical glasses, optoelectronics, and radiation shielding. In this study, the structure of lead-silicate glasses was investigated using molecular dynamics (MD) simulations with Buckingham-type rigid ion potentials combined with Coulomb interactions. Three glass compositions, xPbO–(100 − x)SiO2 with x = 50, 60, and 65 mol%, were examined. In the simulated structures, Si4+ ions are tetrahedrally coordinated with oxygen atoms, with an average coordination number of four. The PbO4 units serve as the fundamental structural motifs in lead-silicate glasses. The number of Pb–Pb nearest neighbors follows a statistical model in which modifier cations (Pb2+) bond to non-bridging oxygens (Onb), and M(Onb)n polyhedra are primarily connected via corner-sharing. The Pb–Pb partial pair distribution function, TPbPb(r), exhibits a peak height that increases with PbO concentration, as expected. The distribution of Qn species varies systematically with silica content, reflecting the depolymerization of the silicate network upon the addition of lead oxide. All structural models demonstrate good agreement with experimental data and Reverse Monte Carlo (RMC) modeling results, including parameters such as short-range order, average bond lengths, bond angle distributions, and Qn species distributions.