HR: 14:55h
AN: P13G-02    [Abstracts]
TI: Laboratory Studies of Organic Compounds With Reflectance Spectroscopy
AU: * Curchin, J M
EM: jcurchin@usgs.gov
AF: USGS, MS 964 Box 25046 W. Sixth Ave. & Kipling St., Denver, CO 80224, United States
AU: Clark, R N
EM: rclark@usgs.gov
AF: USGS, MS 964 Box 25046 W. Sixth Ave. & Kipling St., Denver, CO 80224, United States
AU: Hoefen, T M
EM: thoefen@usgs.gov
AF: USGS, MS 964 Box 25046 W. Sixth Ave. & Kipling St., Denver, CO 80224, United States
AB: In order to properly interpret reflectance spectra of any solar system surface from the earth to the Oort cloud, laboratory spectra of candidate materials for comparative analysis are needed. Although the common cosmochemical species (H2O, CO2, CO, NH3, and CH4) are well represented in the spectroscopic literature, comparatively little reflectance work has been done on organics from room to cryogenic temperatures at visible to near infrared wavelengths. Reflectance spectra not only enhance weak or unseen transmission features, they are also more analogous to spectra obtained by spacecraft that are imaging such bodies as giant planet moons, kuiper belt objects, centaurs, comets and asteroids, as well as remote sensing of the earth. The USGS Spectroscopy Laboratory is measuring reflectance spectra of organic compounds from room to cryogenic temperatures over the spectral range of 0.35 to 15.5 microns. This region encompasses the fundamental absorptions and many overtones and combinations of C, H, O, and N molecular bonds. Because most organic compounds belong to families whose members have similar structure and composition, individual species identification within a narrow wavelength range may be ambiguous. By measuring spectral reflectance of the pure laboratory samples from the visible through the near and mid-infrared, absorption bands unique to each can be observed, cataloged, and compared to planetary reflectance data. We present here spectra of organic compounds belonging to five families: the alkanes, alkenes, alkynes, aromatics, and cyanides. Common to all of these are the deep C-H stretch fundamental absorptions, which shift shortward from 3.35+ microns in alkanes to 3.25+ microns in aromatics, to 3.2+ microns in alkenes, and down to 3.0+ microns in alkynes. Mid-IR absorptions due to C-H bending deformations at 6.8+ and 7.2+ microns are also identified. In the near infrared these stretching and bending fundamentals yield a diagnostic set of combination absorptions at approximately 2.3 microns, as well as the first C-H stretching overtones at 1.6 to 1.7 microns, and even the second stretching overtones at 1.2+ microns. Additionally, the spectral properties of these organic materials have applications to remote sensing of terrestrial environments, including hazardous waste and disaster site characterization.
UR: http://speclab.cr.usgs.gov/
DE: 6211 Centaurs
DE: 6218 Jovian satellites
DE: 6224 Kuiper belt objects
DE: 6280 Saturnian satellites
DE: 6285 Trans-Neptunian objects
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting