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The origin of diamonds in meteorites on the basis of Raman spectra.

基于拉曼光谱的陨石中钻石的起源。

基本信息

批准号：
01420014
负责人：
MIYAMOTO Masamichi
金额：
$ 15.55万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01420014/
关键词：
Raman spectra Meteorite Diamond CVD Spectroscopy X ray diffraction Olivine Residual Stress 気相合成惑星科学宇宙化学

项目摘要

We measured Raman spectra of various diamonds and the full width at half maximum(FWHM)and wavenumber position of a Raman line near 1332 cm^<-1> are compared to better understand the origin of FWHM(2-4 cm^<-1>)like the diamonds from the earth. The FWHMs of Raman peaks of the shock-produced diamonds are largely deviated(10-120 cm^<-1>)and the peak position is significantly shifted to smaller wavenumber up to 1314 cm^<-1>. The FWHM of CVD diamonds ranges from 3 to 25 cm^<-1> and the peak position ranges from 1340 to 1328 cm^<-1>. The peak position of ureilite diamonds ranges from 1334 to 1328 cm^<-1>,which is scattered compared with the diamonds synthesized under static high pressure. The FWHM of ureilites diamonds ranges from 3 to 15 cm^<-1>,which is larger than that of the diamonds synthesized under static high pressure but is smaller than that of the shock-produced diamonds.The peak positions of some ureilite diamonds are shifted to smaller wavenumber,probably due to lonsdaleite(hexagonal diamond). The FWHM of ureilite diamonds is closer to that of CVD diamonds and evidently smaller than that of the shock-produced diamonds. Our results suggest that ureilite diamonds formed from vapor in the primitive solar nebula by chemical vapor deposition. Since duration of shock pressure caused by impact between planetary bodies is longer than that by laboratory experiments,crystallinity of shock-produced diamonds by planetary scale collisions may be improved during longer duration of shock pressure. This may cause a smaller value of the FWHM of the Raman line of diamondSingle-crystal X ray diffraction study with the Laue method using synchrotron radiation showed that a CVD diamond is polycrystalline and disordered and that the cell constant is slightly larger compared with natural diamond.Precise measurement of the peak position of Raman lines of gives information on the residual stress in minerals.

我们测量了各种钻石的拉曼光谱，并比较了半最大值全宽度（FWHM）和拉曼线在1332 cm^<-1>附近的波数位置，以便更好地了解FWHM（2-4 cm^<-1>）与地球钻石相似的起源。冲击产生的金刚石的拉曼峰的fwhm很大程度上偏离（10-120 cm^<-1>），峰值位置明显移动到较小的波数，达到1314 cm^<-1>。CVD金刚石的FWHM范围为3 ~ 25 cm^<-1>，峰位范围为1340 ~ 1328 cm^<-1>。uilite钻石的峰位在1334 ~ 1328 cm^<-1>之间，与静态高压下合成的钻石相比，分布较为分散。uilites金刚石的FWHM范围为3 ~ 15 cm^<-1>，比静态高压下合成的金刚石的FWHM大，但比激波下合成的金刚石的FWHM小。某些菱形钻石的峰位移到较小的波数，这可能是由于菱形钻石（六边形钻石）。uilite金刚石的FWHM更接近CVD金刚石的FWHM，且明显小于冲击生成金刚石的FWHM。我们的研究结果表明，原始太阳星云中的水蒸气通过化学气相沉积形成了uilite钻石。由于行星体之间碰撞产生的冲击压力持续时间比实验室实验的时间长，因此在较长的冲击压力持续时间下，行星尺度碰撞产生的冲击钻石的结晶度可能会得到改善。这可能导致金刚石拉曼线的FWHM值较小。采用同步辐射的Laue方法进行的单晶X射线衍射研究表明，CVD金刚石是多晶且无序的，细胞常数比天然金刚石略大。精确测量拉曼线的峰值位置可以提供矿物中残余应力的信息。