The room temperature electron paramagnetic resonance (EPR) and optical absorption studies of PbO-Li₂O-As₂O₃-B₂O₃ glasses have been done by introducing a transition metal ion Cu⁺² ion as a spin probe with fixed mole% in the given glass composition. Glasses containing transition metal (TM) ion give the information of site symmetry around the Cu⁺² ion of the host glass. The EPR spectra of Cu⁺² in all glass samples recorded in the X-band frequency (9.1–9.7 GHz) have similar features. The spin-Hamiltonian parameters have been calculated; the observed values are g_|| > g_⊥ > g_e and A_|| > A_⊥. It suggests that the site symmetry around Cu⁺² ion is tetragonal distorted octahedral and the ground state of Cu⁺² is d_x²_-y² (²B_1g) orbital. The Cu⁺² ion is coordinated with six ligand atoms in a distorted octahedron site symmetry. The optical absorption spectra exhibit a broadband corresponding to d-d transition bonds of Cu⁺² ion. Calculated bonding parameters suggest the covalent nature of in-plane σ-bonding (α²) and pure ionic nature for out-of-plane (β²) and in-plane π-bonding (β₁²). This data is correlated with the theoretical optical basicity (Λ_th) values, and it is observed that the Γ_σ value increases whereas Γ_π values decrease with increasing Λ_th.

中文翻译：

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PbO-Li 2 O-As 2 O 3 -B 2 O 3玻璃中Cu +2的电子顺磁共振和光学性质

PbO-Li ₂ O-As ₂ O ₃ -B ₂ O ₃玻璃的室温电子顺磁共振（EPR）和光吸收研究通过引入过渡金属离子Cu ⁺²离子作为具有固定摩尔数的自旋探针完成在给定玻璃组成中的％。包含过渡金属（TM）离​​子的玻璃可提供主体玻璃的Cu ⁺²离子周围的位置对称信息。在X波段频率（9.1–9.7 GHz）记录的所有玻璃样品中，Cu ⁺²的EPR光谱具有相似的特征。计算了自旋哈密顿参数。观察值为g _||  > 克_⊥ >  g _e和A _||  > 甲_⊥。这表明Cu ⁺²离子周围的位点对称是四方畸变的八面体，Cu ⁺²的基态是d _x ² _{- y} ²（² B _{1 g}）轨道。Cu ⁺²离子以扭曲的八面体位点对称性与六个配体原子配位。光吸收光谱显示出对应于Cu ⁺²离子的dd跃迁键的宽带。计算结合参数表明在平面σ键合的共价性质（α ²）和纯离子性质对于外的平面（β ²）和面内π η-键接（β ₁ ²）。此数据与理论光学碱度（Λ相关_次）的值，它是观察到Γ _σ值增加，而Γ _π值随Λ减少_位。