Optical constants of solid methane
- Cornell Univ., Ithaca, NY (USA). Lab. for Planetary Studies
- Oak Ridge National Lab., TN (USA)
- Maryland Univ., College Park, MD (USA). Dept. of Chemistry and Biochemistry
- National Aeronautics and Space Administration, Moffett Field, CA (USA). Ames Research Center
Methane is the most abundant simple organic molecule in the outer solar system bodies. In addition to being a gaseous constituent of the atmospheres of the Jovian planets and Titan, it is present in the solid form as a constituent of icy surfaces such as those of Triton and Pluto, and as cloud condensate in the atmospheres of Titan, Uranus, and Neptune. It is expected in the liquid form as a constituent of the ocean of Titan. Cometary ices also contain solid methane. The optical constants for both solid and liquid phases of CH{sub 4} for a wide temperature range are needed for radiative transfer calculations, for studies of reflection from surfaces, and for modeling of emission in the far infrared and microwave regions. The astronomically important visual to near infrared measurements of solid methane optical constants are conspicuously absent from the literature. We present preliminary results of the optical constants of solid methane for the 0.4 {mu}m to 2.6 {mu}m region. We report k for both the amorphous and the crystalline (annealed) states. Using our previously measured values of the real part of the refractive index, n, of liquid methane at 110{degree}K (Bull. Am. Phys. Soc.31, 700 (1986)) we compute n for solid methane using the Lorentz-Lorentz relationship. Work is in progress to extend the measurements of optical constants n and k for liquid and solid to both shorter and longer wavelengths, eventually providing a complete optical constants database for condensed CH{sub 4}. 33 refs., 6 figs., 2 tabs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- DOE/ER; National Aeronautic and Space Administration (NASA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6279633
- Report Number(s):
- CONF-8910341-1; ON: DE91004531; CNN: NGR 33-010-220; NGR 33-010-082; NAGW 637
- Resource Relation:
- Conference: 1. international conference on laboratory research for planetary atmospheres, Bowie, MD (USA), 25 Oct 1989
- Country of Publication:
- United States
- Language:
- English
Similar Records
Upper limits of possible photochemical hazes on Pluto
Physics and Advanced Technologies LDRD Final Report:Adaptive Optics Imaging and Spectroscopy of the Solar System