Raman Micro-Spectroscopy Of Nanodiamonds From The Kapoeta Meteorite

Nanodiamonds, found in a carbonaceous-chondrite material from the gas-rich meteorite Kapoeta, have been studied by micro-Raman spectroscopy. The Raman spectra of these nanodiamonds show the first-order Raman peak of diamond at 1333 cm(-1), along with the "D" and "G" peaks of graphitic/amorphous carbon phases. The spectra also show additional Raman peaks and features that are attributable to trans-polyacetylene at grain boundaries of the nanocrystalline diamonds, tetrahedral amorphous carbon, and presence of nitrogen and hydrogen. The spectra and the associated parameters are very similar to those of chemical-vapor-deposition (CVD) nanocrystalline diamonds and may suggest a similar formation process for the Kapoeta nanodiamonds, possibly in the solar nebula. The Kapoeta nanodiamonds and the associated amorphous carbon phases are probably the main carriers of the abundant noble gases found in the Kapoeta meteorite.