Understanding the connection of molecular structure and optical properties of rare earth doped luminescent materials is essential for fabrication of state-of-the-art active laser media. On the other hand, rare earth ions can be used as a probe ion for the molecular structure of the host material if the structure-property correlations are known. Therefore, this work combines molecular dynamics simulations, Judd-Ofelt theory and UV–vis-NIR absorption spectroscopy including the behavior of the structure-sensitive hypersensitive absorption transitions of Er³⁺ to expand the knowledge on the local molecular structure in the immediate vicinity of the doped rare earth ions in dependence of glass composition. For this purpose, glasses of the compositions (35-x) BaO · x MgO · 10 Al₂O₃ · 55 SiO₂ (mol%) (x = 0, 7.5, 15, 25, 35) and (20-x) BaO · x MgO · 20 Al₂O₃ · 60 SiO₂ (mol%) (x = 0, 10, 20), doped with 2 × 10²⁰ ions/cm³ Er³⁺ were prepared and analyzed. Clear differences in the absorption spectra between glasses of different BaO/MgO ratios, i.e. different network modifier field strengths, and different network modifier oxide to Al₂O₃ ratios are found and discussed in detail. Glasses with high BaO concentrations and high network modifier oxide to Al₂O₃ ratios provide lower rare earth coordination numbers with oxygen in general but higher coordination probabilities with non-bridging oxygen, which results in notably increased splitting of the optical transitions of the doped rare earth ions and higher hypersensitivity / lower local site symmetry for the doped rare earth ions in the investigated compositions. Based on our results and results from other publications the local rare earth site symmetry in glasses can in general be correlated with the rare earth coordination number.

了解稀土掺杂发光材料的分子结构和光学特性之间的联系对于制造最先进的有源激光介质至关重要。另一方面，如果已知结构-性质相关性，稀土离子可用作主体材料分子结构的探针离子。^{因此，这项工作结合了分子动力学模拟、Judd-Ofelt 理论和 UV-vis-NIR 吸收光谱，包括 Er 3+}的结构敏感超敏吸收跃迁的行为，以扩展对紧邻的局部分子结构的认识掺杂的稀土离子取决于玻璃成分。为此，组成 (35-x) BaO · x MgO · 10 Al ₂ O的玻璃₃ · 55 SiO ₂ (mol%) ( x  = 0, 7.5, 15, 25, 35) and (20-x) BaO · x MgO · 20 Al ₂ O ₃ · 60 SiO ₂ (mol%) ( x  = 0 , 10, 20),制备并分析了掺杂有 2 × 10 ²⁰离子/cm ³ Er ^{3+ 。}发现并详细讨论了不同 BaO/MgO 比率（即不同网络改性剂场强和不同网络改性剂氧化物与 Al ₂ O ₃比率）的玻璃之间吸收光谱的明显差异。具有高 BaO 浓度和针对 Al ₂ O _{3的高网络改性剂氧化物的玻璃}一般而言，稀土与氧的配位数较低，但与非桥接氧的配位数较高，这导致掺杂稀土离子的光学跃迁分裂显着增加，掺杂稀土的超敏性/局部位点对称性较低所研究组合物中的离子。根据我们的结果和其他出版物的结果，玻璃中的局部稀土位点对称性通常与稀土配位数相关。