Abstract The deconvolution and resolution of overlapping bands in the Raman spectra of a suite of coals studied by curve-fitting methods has improved our understanding of the main structural changes in naturally matured coals. Even though much work on deconvolution of Raman spectra has been done, the systematic evolution of chemical structures is not well established. In this study we used a suite of 28 coal samples from Australia with vitrinite reflectance ranging from 0.38 to 3.52%. The micro-Raman spectra of vitrinite macerals from selected coals were acquired using a custom-made Raman spectrometer and supplemented by other Raman spectra previously acquired under the same experimental conditions. In the spectral deconvolution procedure, the second derivative curve-fitting method was used to determine the number of peaks and peak positions of the Raman spectra. Each band was tentatively assigned to a corresponding chemical structure by references to the interpreted major structural changes likely to have taken place during coalification. These parameters included PD (the position of D band), RBS (the distance between G band and D band), FWHMG (full width at half maximum of G band), IG/IGL (the intensity ratio of G band and GL band), and AR/b (the ratio of Raman integrated area and the slope of the spectral background). All of these Raman parameters are found to have a very good correlation with Ro% with R2 higher than 0.90. While five simple equations have been proposed and may be used to estimate thermal maturity of coals, two equations (Eq. (4) for Ro% from 0.38 to 1.5 and Eq. (5) for Ro% from 1.5 to 3.52) are best suitable to predict thermal maturity of coals with the most accuracy.

中文翻译：

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澳大利亚一组煤镜质体化学结构和热成熟度的拉曼光谱研究

摘要 通过曲线拟合方法研究的一组煤的拉曼光谱中重叠带的解卷积和分辨率提高了我们对自然成熟煤的主要结构变化的理解。尽管已经做了很多关于拉曼光谱去卷积的工作，但化学结构的系统演化还没有很好地建立。在这项研究中，我们使用了一组来自澳大利亚的 28 个煤样，其镜质体反射率范围为 0.38% 到 3.52%。使用定制的拉曼光谱仪获得选定煤的镜质体微拉曼光谱，并辅以先前在相同实验条件下获得的其他拉曼光谱。在光谱解卷积过程中，采用二阶导数曲线拟合法确定拉曼光谱的峰数和峰位置。通过参考解释的可能在煤化过程中发生的主要结构变化，将每个带暂时分配给相应的化学结构。这些参数包括PD（D带的位置）、RBS（G带和D带之间的距离）、FWHMG（G带半高宽）、IG/IGL（G带和GL带的强度比） , 和 AR/b（拉曼积分面积与光谱背景斜率的比值）。发现所有这些拉曼参数与 Ro% 具有很好的相关性，R2 高于 0.90。虽然已经提出了五个简单的方程并可用于估计煤的热成熟度，但有两个方程（方程 (4) 用于 Ro% 从 0.38 到 1.5 和方程。