Optical Properties and Structure of As–Sb Chalcohalide Glasses by Raman Scattering and Density Functional Theory Calculations,The Journal of Physical Chemistry B

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Optical Properties and Structure of As–Sb Chalcohalide Glasses by Raman Scattering and Density Functional Theory Calculations
The Journal of Physical Chemistry B ( IF 2.8 ) Pub Date : 2020-03-25 , DOI: 10.1021/acs.jpcb.0c00799
G. R. Štrbac ₁ , S. R. Lukić-Petrović ₁ , D. D. Strbac _{1,

2} , V. Benekou ₃ , A. Chrissanthopoulos ₄ , S. N. Yannopoulos ₃

Affiliation

We report an investigation of the optical properties, structure, and vibrational modes of Sb_xAs_37–xS₄₈I₁₅ glasses (0 at. % < x < 37 at. %). Optical parameters such as the refractive index, the absorption coefficient, and the optical band gap are correlated with the glass composition. All parameters were found to follow an almost linear dependence with the antimony content x. Both the refractive index and the absorption edge wavelength exhibit a systematic increase against x. Off-resonant Raman spectra of the glasses spectra were measured and analyzed. Structural units, representative of the glass structure, were optimized by density functional theory (DFT) calculations, providing vibrational spectra in agreement with the experiments. Raman spectra were interpreted based on the harmonic frequencies and the activities of vibrational modes obtained by the DFT analysis. The results showed evidence in favor of statistical mixing of iodine atoms, among the various pyramidal units, hence discarding structural models suggesting the presence of isolated pyramidal molecules of the types AsI₃/SbI₃. Both experimental data and DFT results suggested that iodine atoms exhibit much higher propensity to replace sulfur atoms in antimony than in arsenic-based pyramids. In addition, comparison of experimental and simulated spectra of selected clusters in mixed glasses indicates that it is more probable to find corner-sharing Sb-based pyramids than As-based ones.

中文翻译：

拉曼散射和密度泛函理论计算As-Sb卤化玻璃的光学性质和结构

我们报告了对Sb _x As _{37– x} S ₄₈ I ₁₅玻璃（0 at。％< x <37 at。％）的光学性质，结构和振动模式的研究。诸如折射率，吸收系数和光学带隙的光学参数与玻璃组成相关。发现所有参数都与锑含量x几乎呈线性关系。折射率和吸收边缘波长相对于x都显示出系统的增加。测量并分析了眼镜光谱的非共振拉曼光谱。通过密度泛函理论（DFT）计算优化了代表玻璃结构的结构单元，并提供了与实验一致的振动光谱。拉曼光谱是根据谐波频率和通过DFT分析获得的振动模式的活动来解释的。结果表明，有证据支持在不同的锥体单元中碘原子的统计混合，因此丢弃结构模型表明存在分离的AsI ₃ / SbI ₃类型的锥体分子。实验数据和DFT结果均表明，与锑基金字塔相比，碘原子在锑中取代硫原子的可能性更高。此外，对混合玻璃中选定簇的实验光谱和模拟光谱进行的比较表明，找到比Sr基棱角共享的基于Sb角锥的金字塔更有可能。

更新日期：2020-03-26

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