A combined ⁷⁷Se NMR and Raman spectroscopic study of the structure of Ge_xSe_1-x glasses: Towards a self consistent structural model

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• 作者：Trenton G. Edwards ; Sabyasachi Sen ; ^{sbsen@ucdavis.edu} ; Erica L. Gjersing
• 关键词：Germanium selenide glass ; Chalcogenide glass ; Structure ; 77Se NMR spectroscopy ; Raman spectroscopy
• 刊名：Journal of Non-Crystalline Solids
• 出版年：2012
• 出版时间：1 February 2012
• 年：2012
• 卷：358
• 期：3
• 页码：609-614
• 全文大小：894 K

文摘

The short-range structures of stoichiometric and Se-deficient binary Ge_xSe_100 ?em>x glasses with 42 ?#xA0;x ?#xA0;33.33 have been investigated using a combination of Raman and ⁷⁷Se Car-Purcell-Meiboom-Gill (CPMG) spikelet nuclear magnetic resonance (NMR) spectroscopy. When taken together, these spectroscopic results allow for self-consistent assignment of average ⁷⁷Se NMR isotropic chemical shifts to Se atoms in various coordination environments in Ge_xSe_100 ?em>x glasses. Analysis of the compositional variation of the relative concentrations of these Se environments indicates considerable violation of chemical order in the nearest-neighbor coordination environments of the constituent atoms in the stoichiometric Ge_33.33Se_66.67 glass. On the other hand, the presence of a random distribution of Ge¨DGe bonds can be inferred in the Se-deficient glasses. Simulations of the previously published ⁷⁷Se NMR line shapes of Se-excess glasses on the basis of the revised structural assignments of ⁷⁷Se NMR chemical shifts obtained in this study conclusively indicate that the structure of these glasses is intermediate between a randomly connected and a fully clustered network of GeSe₄ tetrahedra and Se chains.