ICSE Digital Repository
  ICSE People Digital Repository Interactive Map Contact  

Advanced Search
Repository Home
 
Browse
Issue Date
Author
Title
Publisher
 
Others
Login
Repository Software

DSpace at ICSE  >
ICSE Public Community >
ICSE Digital Library >


Title: Optical constants of kerogen from 0.15 to 40 µm: Comparison with meteoritic organics
Authors: Khare, Bishun N.
Thompson, W. R.
Sagan, C.
Arakawa, E. T.
Meisse, C.
Gilmour, I.
Issue Date: 1991
Publisher: Oak Ridge National Laboratory
Citation: Proceedings: International Conference on Laboratory Research for Planetary Atmospheres, Second; pp. 340-356 (1991)
Type: conference publication
Pages: 20
Abstract: Kerogens are dark, complex organic materials produced on the Earth primarily by geologic processing of biologic materials, but kerogens have chemical and spectral similarities to some classes of highly processed extraterrestrial organic materials. Kerogen-like solids have been proposed as constituents of the very dark reddish surfaces of some asteroids [Gradie and Veverka, Nature 283. 840 (1980)] and are also spectrally similar to some carbonaceous organic residues and the lapetus dark material [Cruikshank et al.. Icarus 53. 90 (1983)]. Kerogen can thus serve as a useful laboratory analogue to very dark, spectrally red extraterrestrial materials; its optical constants can be used to investigate the effects of particle size, void spice and mixing of bright and dark components in models of scattering by dark asteroidal. cometary, and satellite surfaces. We report measurements of the optical constants of both Type II kerogen and of macromolecular organic residue from the Murchison carbonaceous chondrite via transmission and eflection measurements on thin films. These films, of thickness 0.2- 1.3 um. are produced by vacuum deposition of kerogen powder heated to 550-750°C onto sapphire. CaF2, and Csl substrates. IR spectra of the thin fiims show that the spectral features of the kerogen powder are retained. Apparently no substantial change in optical constants occurs upon vacuum deposition, except for the desirable loss of silicate contaminants which can be seen in the spectra of the powder. The real part of the refractive index, n. is determined by variable incidence angle reflectance to be 1.60 ± 0.05 from 0.4-2.0 um wavelength. Work extending the measurement of n to longer wavelengths is in progress. The imaginary part of the refractive index. k. shows substantial structure from 0.15-40 um,. The values are accurate to ± 20% in the UV and IR regions and to r 30% in the visible. We have also measured k values of organic residues from me Murchison meteorite. Comparison of the kerogen and Murchison data reveals mat between 0.15 and 4j um. Murchison has a similar structure but no bands as sharp as in Kerogen. and that the /. values for Murchison are significantly higner man those of kerogen.
URI: http://ds.heavyoil.utah.edu/dspace/handle/123456789/7950
Appears in Collections:ICSE Digital Library

Files in This Item:

File Description SizeFormat
6151415.pdfOCR116.16 kBAdobe PDFView/Open
o_6151415.pdforiginal951 kBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 
Valid XHTML 1.0! DSpace Software Copyright © 2002-2009  The DSpace Foundation - Feedback