DPS 2001 meeting, November 2001
Session 56. Laboratory Studies Posters
Displayed, 9:00am Tuesday - 3:00pm Saturday, Highlighted, Saturday, December 1, 2001, 2:00-2:30pm, French Market Exhibit Hall

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[56.08] Vacuum ultraviolet molecular nitrogen photoabsorption cross sections for planetary atmospheric transmission models

G. Stark (Physics Department, Wellesley College), P. L. Smith, K. Yoshino, J. Rufus (Harvard-Smithsonian Center for Astrophysics), K. P. Huber (Steacie Inst. Molecular Sciences, NRC Canada)

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. In particular, there is a need for reliable photoabsorption f-values and line widths for the ~ 100 electronic bands of N2 in the 80 to 100 nm wavelength region. As part of our continuing program of laboratory measurements and analyses of the N2 VUV absorption spectrum, we present the results of new measurements of individual line strengths and widths in selected bands. These results indicate that within a number of individual bands there are significant departures from the predicted line strength distributions based on isolated band models. New line width measurements in the 95 to 100 nm region are also presented and compared to other values found in the literature.

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 The archive includes published and unpublished 14N2, 14N15N, and 15N2 line lists and spectroscopic identifications, excited state energy levels, band and line f-values, a summary of published band f-value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-Seidel grant program.

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