Absorption Spectra and Absorption Coefficients for Methane in the 750-940 nm region obtained by Intracavity Laser Spectroscopy

Details Absorption Spectra and Absorption Coefficients for Methane in the 750-940 nm region obtained by Intracavity Laser Spectroscopy Absorption Spectra and Absorption Coefficients for Methane in the 750-940 nm region obtained by Intracavity Laser Spectroscopy

Oct 2000

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000dps....32.5711o&link_type=abstract

American Astronomical Society, DPS Meeting #32, #57.11; Bulletin of the American Astronomical Society, Vol. 32, p.1110

Astronomy and Astrophysics

Astronomy

Scientific paper

Methane spectral features are prominent in the reflected sunlight spectra from the outer planets and some of their major satellites and can provide useful information on the atmospheres of those bodies. Methane bands occurring in the visible to near-IR region are particularly important because for many of these planetary bodies, methane bands occurring in the IR are saturated. Spectral observations of these bodies also are being made at increasingly higher resolution. In order to interpret the planetary spectra, laboratory data for methane obtained at appropriate sample conditions and spectral resolution are required. Since the visible to near-IR spectrum of methane is intrinsically weak, sensitive techniques are required to perform the laboratory measurements. We have employed the intracavity laser spectroscopy (ILS) technique to record methane spectrum in the visible to near-IR region. New results for room temperature methane in the 10,635 - 13,300 cm-1 region and for liquid nitrogen temperature (77 K) methane in the 10,860 - 11,605 cm-1 region will be presented. Spectra throughout the more strongly absorbing sections will be shown. These spectra are acquired at a resolution of 400,000 - 500,000 and are calibrated using iodine reference spectra acquired from an extra-cavity cell at nearly the same time as when the methane data are recorded. From the spectra, absorption coefficients are determined and these are presented as averages over 1 Å and 1 cm-1 intervals. In order to obtain the results, spectra are deconvolved for the instrument function using a Fourier transform technique. The validity of the approach is verified from studies of isolated oxygen lines in the A band occurring around 760 nm. Good agreement is observed between the intensity values determined from the FT deconvolution and integration method and those derived by fitting the observed line profiles to Voigt line-shapes convoluted with the instrument function. The methane results are compared with low-resolution measurements on methane at room temperature and with absorption coefficients derived from methane features observed in spectra of the outer planets and Titan. This research was supported by NASA's Planetary Atmospheres Program under grant number NAG5-6091.

Affiliated with

Also associated with

No associations

Rating

Absorption Spectra and Absorption Coefficients for Methane in the 750-940 nm region obtained by Intracavity Laser Spectroscopy does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Absorption Spectra and Absorption Coefficients for Methane in the 750-940 nm region obtained by Intracavity Laser Spectroscopy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Absorption Spectra and Absorption Coefficients for Methane in the 750-940 nm region obtained by Intracavity Laser Spectroscopy will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-867705