The Raman spectra of the end member pyroxenes CaZnSi2O6 and Zn2Si2O6 are calculated by quantum mechanical modeling and compared with the experimental ones measured in synthetic (CaxZn1−x)ZnSi2O6 pyroxenes with x = 0, 0.2, 0.3, 0.5, 0.7, 1. The calculated spectra correctly predict the intensity and peak positions of the spectra recorded on the end members. The model provides also useful hints for the mode assignment at the intermediate compositions. The experimental peak positions are compared in (CaxM2+1−x)M2+Si2O6 pyroxenes, with M2+ = Mg, Co, Zn, Fe2+. These pyroxenes share a common charge and different mass and ionic radius; the relative contributions of the mass and ionic radius in the experimental spectrum are discussed in four of the most intense peaks. We found that the positions of the strongest peaks are related to the average bond distances of the polyhedra which most affect a given mode. Ca–Zn pyroxenes provide an exception, whereas the CaZnSi2O6 end member fits quite well in the bond-distance/peak positions relations found in other pyroxenes, and the same does not occur as Zn exchanges for Ca. Peak broadening occurs in Zn pyroxenes in intermediate compositions; it is related to the presence of polyhedral local configurations around Zn and Ca atoms in the M2 polyhedron. The broadening is higher in the ~ 1010 cm−1 peak (ν19), which, among the strongest peaks, shows the highest difference in the Raman wavenumber between end members. The different behaviours of Zn pyroxenes with respect to Mg, Co, and Fe2+ ones are likely related to the partially covalent bonding in the M2 cavity shown by Zn pyroxenes.

中文翻译：

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Ca-Zn 辉石的实验和计算拉曼光谱以及 (CaxM2+1−x)M2+Si2O6 辉石之间的比较（M2+ = Mg、Co、Zn、Fe2+）

端元辉石 CaZnSi2O6 和 Zn2Si2O6 的拉曼光谱是通过量子力学模型计算的，并与在合成 (CaxZn1-x)ZnSi2O6 辉石中测量的实验光谱进行比较，x = 0, 0.2, 0.3, 0.5, 0.7, 1。计算结果光谱正确预测记录在末端构件上的光谱的强度和峰值位置。该模型还为中间组合的模式分配提供了有用的提示。实验峰位置在 (CaxM2+1−x)M2+Si2O6 辉石中进行比较，其中 M2+ = Mg、Co、Zn、Fe2+。这些辉石具有共同的电荷和不同的质量和离子半径；实验光谱中质量和离子半径的相对贡献在四个最强烈的峰中进行了讨论。我们发现最强峰的位置与对给定模式影响最大的多面体的平均键距有关。Ca-Zn 辉石提供了一个例外，而 CaZnSi2O6 端元非常适合其他辉石中发现的键距/峰位置关系，并且在 Zn 交换 Ca 时不会发生同样的情况。中间组合物中的锌辉石出现峰展宽；它与 M2 多面体中 Zn 和 Ca 原子周围多面体局部构型的存在有关。~ 1010 cm-1 峰 (ν19) 的展宽更高，在最强的峰中，其显示端部成员之间的拉曼波数差异最大。Zn 辉石相对于 Mg、Co、