HR: 0830h
AN: P21B-07    [Abstracts]
TI: Laboratory Measurements of Molecular Nitrogen Vacuum Ultraviolet Photoabsorption Cross Sections and Line Widths in Support of Analyses of Titan's Atmosphere
AU: * Stark, G
EM: gstark@wellesley.edu
AF: Physics Department, Wellesley College, 106 Central Street, Wellesley, MA 02481 United States
AU: Smith, P L
EM: plsmith@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 United States
AU: Yoshino, K
EM: kyoshino@cfa.harvard.edu
AF: Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 United States
AB: The analyses of upcoming VUV occultation measurements of the N2-rich atmosphere of Titan will require reliable photoabsorption cross sections and line widths for the 100 electronic bands of N2 in the 80 to 100 nm wavelength region. We report measurements of these fundamental parameters of the absorption spectrum of 14N2 in the 93.5 - 100 nm spectral region. The room temperature absorption measurements were performed with the 6.65-meter vuv spectrometer at the Photon Factory synchrotron facility with a resolving power of approximately 125,000. A line-shape fitting routine is used to extract individual rotational line f-values and predissociation-broadened line widths within the fifteen bands reported in this study. Within individual bands, we find significant departures from the predicted line strength distributions based on isolated band models. Line width analyses within each band indicate that predissociation-broadening is often highly dependent on the rotational quantum number. We illustrate the importance of N2 line widths in the analysis of Cassini occultation measurements with sample N2 transmission models over selected wavelength regions.
DE: 5405 Atmospheres--composition and chemistry
DE: 6280 Saturnian satellites
SC: Planetary Sciences [P]
MN: 2005 Joint Assembly