The Open UniversitySkip to content
 

FT–IR microspectroscopy of extraterrestrial dust grains: Comparison of measurement techniques

Morlock, A.; Kohler, M.; Bowey, J. E. and Grady, Monica M. (2006). FT–IR microspectroscopy of extraterrestrial dust grains: Comparison of measurement techniques. Planetary and Space Science, 54(6) pp. 599–611.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1016/j.pss.2006.02.002
Google Scholar: Look up in Google Scholar

Abstract

Identification of astronomical dust composition rests on comparison of Infrared (IR) spectra with standard laboratory spectra; frequently, however, a single mineralogical composition is assumed for spectral matching. Advances in laboratory instrumentation have enabled very precise IR spectra to be measured on single grains and zones within grains; with a more complete set of spectral data for planetary dust, better compositional matches will be achieved for astronomical dust. We have compared several FT–IR spectroscopy techniques (open path transmission spectroscopy and diffuse reflectance spectroscopy of powders; microspectroscopy of single grains and powders and ATR spectroscopy of thin sections) to determine their utility for the direct measurement of the mid-IR spectra of small amounts of extraterrestrial grains. We have focussed our investigation on the spectra of the olivine series of silicates, (Mg,Fe)2SiO4, a species frequently identified as one of the major constituents of interstellar dust. The positions of three characteristic SiO4 stretching bands at 10.4, 11.3 and 12 μm were measured for comparison of the techniques. All methods gave satisfactory results, although care must be taken to guard against artefacts from sample thickness and orientation effects. Single grains hand-picked from meteorites can be analysed, but results are inaccurate if the grain size is too large (>1–10 μm). Spectra for single grains also show variations that arise from sample orientation effects. Once the analytical artefacts are taken into account, we found that measurement of powder with a diamond compression cell is best suited for the analysis of small amounts of materials.

Item Type: Journal Article
ISSN: 0032-0633
Keywords: Infrared; dust; technique; spectroscopic; methods; laboratory
Academic Unit/Department: Science > Physical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 7905
Depositing User: Kyra Proctor
Date Deposited: 06 Jun 2007
Last Modified: 02 Dec 2010 19:59
URI: http://oro.open.ac.uk/id/eprint/7905
Share this page:

Altmetrics

Scopus Citations

Actions (login may be required)

View Item
Report issue / request change

Policies | Disclaimer

© The Open University   + 44 (0)870 333 4340   general-enquiries@open.ac.uk