Raman spectroscopic study of diamond and graphite in ureilites and the origin of diamonds
Raman spectroscopic study of diamond and graphite in ureilites and the origin of diamonds
复制标题
尿素岩中金刚石和石墨的拉曼光谱研究及金刚石的起源
DOI：
--
复制
发表时间：
2012
期刊：
影响因子：
--
通讯作者：
J. Matsuda
中科院分区：
文献类型：
--
作者：
K. Nagashima;M. Nara;J. Matsuda
摘要-我们对艾伦山A77257、西北非洲3140、Shişr007、Yamato 790981(Y-790981)和Yamato 791538(Y-791538)五个铀矿中的碳脉进行了显微拉曼光谱分析。石墨峰表明，透辉石中的石墨结构发达，尤其是与碳质球粒陨石中的碳质物质相比。石墨的微区尺寸为45-110 ä。我们观察到钻石峰位向更高的波数移动，具有较大的半高半宽(FWHM)，特别是对NWA3140。虽然钻石峰值的半高宽不是对化学气相沉积(CVD)钻石起源的关键诊断测试，但钻石峰值向更高波数的移动可能是支持CVD起源的一个强有力的指标，因为这些移动只在CVD钻石中观察到。我们从多个方面讨论了金刚石的起源，并确认了CVD模型是最可信的。我们的结论是，所有的碳材料(石墨、无定形碳、钻石等)凝聚在原始太阳星云中的早期凝聚物上。
Abstract– We performed micro‐Raman spectroscopic analyses of the carbon vein in five ureilites: Allan Hills (ALH) A77257, Northwest Africa (NWA) 3140, Shişr 007, Yamato 790981 (Y‐790981), and Yamato 791538 (Y‐791538). The graphite peaks showed that the graphite structure in ureilite is well developed, especially compared with the carbonaceous material in carbonaceous chondrite. The domain sizes of the graphite were 45–110 Å. We observed shifts in the diamond peak positions to higher wave numbers with a large full width at half maximum (FWHM), especially for NWA 3140. Although the FWHM of a diamond peak is not a crucial diagnostic test for a chemical vapor deposition (CVD) origin of diamond, the shift of the diamond peaks to higher wave numbers could be a strong indicator that supports the CVD origin as these shifts have only been observed in CVD diamonds. We discuss the origin of diamond from various aspects, and confirm that the CVD model is the most plausible. We conclude that all carbon material (graphite, amorphous carbon, diamond, etc.) condensed on the early condensates in the primitive solar nebula.