DPS 35th Meeting, 1-6 September 2003
Session 16. Laboratory Research II
Poster, Highlighted on, Wednesday, September 3, 2003, 3:00-5:30pm, Sierra Ballroom I-II

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[16.07] Laboratory measurements of VUV N2 photoabsorption cross sections and line widths: applications to planetary atmospheric transmission models

P. L. Smith (Harvard-Smithsonian CfA), G. Stark (Physics Dept., Wellesley College), K. Yoshino (Harvard-Smithsonian CfA)

The analyses of VUV occultation measurements of the N2-rich atmospheres of Titan and Triton are hampered by the lack of fundamental spectroscopic data for N2. There is a need for reliable photoabsorption cross sections and line widths for the ~100 electronic bands of N2 in the 80 to 100 nm wavelength region. We present analyses of new measurements of individual line strengths and widths in N2 bands in the region 94 to 100~nm. 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 occultation measurements via N2 transmission models over selected wavelength regions.

We have continued to compile on-line molecular spectroscopic atlas based on our N2 laboratory data: http://cfa-www.harvard.edu/amdata/ampdata/N2ARCHIVE/n2home.html. The archive includes published and unpublished 14N2, 14N15N, and 15N2 line lists and spectroscopic identifications, excited state energy levels, band and line f-values, a summary of published band f-value and line width measurements, and a cross-referenced summary of the relevant N2 literature. The listings are searchable by wavelength interval or band identification and are suitable for down-loading in a convenient format.

We gratefully acknowledge funding support from NASA grant NAG5-9059 and the Smithsonian Institution Atherton-Seidell Grant Program.

The author(s) of this abstract have provided an email address for comments about the abstract: gstark@wellesley.edu

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.