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ARTICLE

Structural and vibrational characteristics of Ge-S-Br glass system: ab initio calculation and Raman study

X. C. Han, K. Yu, J. Q. Bao, Y. L. Tong^*

Faculty of Information Science and Technology, Wenhua College, Wuhan, 430074, P. R. China

* Corresponding Author:

Chalcogenide Letters 2024, 21(2), 135-150. https://doi.org/10.15251/CL.2024.212.135

Received 26 October 2023; Accepted 05 February 2024;

Abstract

To improve the understanding of the structure network of chalcogenide glass, we report an investigation of the structure and vibrational property of the Ge-S-Br system chalcogenide glass. The structural origin was interpreted by the result of ab initio calculation performed on the basic units such as ethane-like(ETH) structure(Ge₂S₆ and Ge₂Br₆),edge-sharing(ES) structure Ge₂S₂S_nBr_4-n (n=0,1,2,3,4) and isolated GeS_nBr_4-n tetrahedron (n=0,1,2,3,4), which represent the local structure of Ge-S-Br glassy system. In addition, We have compared the experimental spectra of GeS₂, GeS₃Br, GeSBr₂ glasses and liquid GeBr₄ to the calculated main vibrational modes of basic units by ab initio calculation. The calculated vibrational modes of the GeS_nBr_4-n cluster are assigned by group theory. Moreover, the symmetrical stretching modes related to the Ge-S and Ge-Br bond are in accordance with the vibrational coupling theory. The variation of calculated main vibrational modes of GeSmBrn clusters reveals the structure formations of Ge-S-Br glassy system with different S/Br ratios, which can be in agreement with vibrational spectra of Ge-S-Br glass.

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Keywords

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