NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Raman spectroscopic studies of carbon in extra-terrestrial materialsThe measurements obtained here indicate ways in which micro-Raman spectroscopy can be used to elucidate structural characteristics and distribution of carbon in meteorites and interplanetary dust particles (IDPs). Existing information about structurally significant aspects of Raman measurements of graphite is combined with structurally relevant findings from the present micro-Raman studies of carbons prepared by carbonization of polyvinylidine chloride (PVDC) at various temperatures and natural material, as well as several acid residues from the Allende and Murchison meteorites in order to establish new spectra-structure relationships. Structural features of many of the materials in this study have been measured by x ray analysis and electron microscopy: thus, their structural differences can be directly correlated with differences in the Raman spectra. The spectral parameters consequently affirmed as indicators of structure are used as a measure of structure in materials that have unknown carbon structure, especially IDPs. The unique applicability of micro-Raman spectroscopy is realized not only in the ability to conveniently measure spectra of micron-size IDPs, but also micro-sized parts of an inhomogeneous material. Microcrystalline graphite is known to give Raman spectra that differ dependent on crystallite size (see e.g., Lespade, et. al., 1984, or Nemanich and Solin, 1979). The spectral changes that accompany decreasing particle size include increase in the ratio (R) of the intensity of the band near 1350 cm(-1) (D band) to that of the band near 1600 cm(-1) (G band) increase in the half width of the D band (wD) increase in the frequency maximum of the G band and increase in the half-width (wG) of the 2nd order band near 2700 cm(-1) (G) band.
Document ID
19900018273
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Macklin, John
(Washington Univ. Seattle., United States)
Brownlee, Donald
(Washington Univ. Seattle., United States)
Chang, Sherwood
(NASA Ames Research Center Moffett Field, CA., United States)
Bunch, Ted
(Washington Univ. Seattle., United States)
Date Acquired
September 6, 2013
Publication Date
April 1, 1990
Publication Information
Publication: Carbon in the Galaxy: Studies from Earth and Space
Subject Category
Astrophysics
Accession Number
90N27589
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available