HR: 0800h
AN: SA11A-0211 [Abstracts]
TI: The Rovibronic Line fVValues of N2 in the 91.6 nm Region: High-Resolution, High-Temperature
AU: * Judge, D L
EM: djudge@usc.edu
AF: University of Southern California, Space Sciences Center, SHS 274, Los Angeles, CA 90089-1341
United States
AU: Wu, R C
EM: robertwu@usc.edu
AF: University of Southern California, Space Sciences Center, SHS 274, Los Angeles, CA 90089-1341
United States
AU: Matsui, T
EM: takashi.matsui@aist.go.jp
AF: National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, Tsukuba, Iba
305-8565
Japan
AB:
We report measurements of the rotational f-values in the high temperature-dependent ultrahigh-resolution photoabsorption of
N2 in the 91.6 nm region. One of the important issues regarding the interpretation of the NII 91.6 nm extreme ultraviolet
airglow emissions of the Earth, Titan, and Triton is the effect of temperature on the atmospheric extinction due to
absorption by N2 and O2. Since the temperature of the upper atmosphere of the Earth is typically in the 200 to 900 K range it
is therefore important to know these molecular cross sections at such temperatures.
Absorption features in this region mainly involve the (11,0) band of the b-X transition, under room temperature conditions.
We have carried out high resolution photoabsorption cross section measurements of N2 with a resolution of 0.0003 nm and
0.0008 nm in the 91.5-91.728 nm region at temperatures of 600, 445, and 295 K. The 6VOPE (6.65-m vertical off-plane Eagle
spectrograph) spectrometer facility available at the Photon Factory, KEK, Tsukuba, Japan, was employed in the present study.
Additional intense rovibronic lines have been observed at high temperature conditions. They are tentatively identified as
rovibronic transitions involving high rotational quantum numbers from the (12,1) band of the b-X, the (8,1) band of the b'-X,
and the (3,1) band of the o3-X transitions.
By integration over each individual absorption profile the rotational line f-values of N2 are determined for the
above-mentioned spectral region and experimental conditions. The most intense component of the NII multiplets at 91.6710 nm
overlap with the rovibronic line Q6 at 91.6703 nm. The NII 91.6710 nm feature is located slightly toward the line center of
the Q6 line of the (11,0) band of the N2 b-X transition. However, at 445 K and 600 K this NII component completely falls
inside the line shape of the Q6 of N2. Detailed results will be presented. This research is based on work supported by NSF
grant ATM-0096761.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0310 Airglow and aurora
DE: 0317 Chemical kinetic and photochemical properties
DE: 0343 Planetary atmospheres (5210, 5405, 5704)
DE: 0350 Pressure, density, and temperature
SC: SPA-Aeronomy [SA]
MN: Fall Meeting 2005