HR: 0800h
AN: A31B-0310    [Abstracts]
TI: Low-Uncertainty Measurements of O2 A-Band Line Positions
AU: Robichaud, D J
EM: djr@its.caltech
AF: Division of Chemistry and Chemical Engineering,California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, United States
AU: * Hodges, J T
EM: joseph.hodges@nist.gov
AF: Process Measurements Division, National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, MD 20899, United States
AU: Piotr, M
EM: pmaslows@nist.gov
AF: Instytut Fizyki, Uniwesytet Mikolaja Kopernika, ul. Grudziadzka 5/7, Torun, 87-100, Poland
AU: Yeung, L Y
EM: lyeung@caltech.edu
AF: Division of Chemistry and Chemical Engineering,California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, United States
AU: Okumura, M
EM: mo@its.caltech.edu
AF: Division of Chemistry and Chemical Engineering,California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, United States
AU: Miller, C E
EM: charles.e.miller@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Brown, L R
EM: Linda.R.Brown@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AB: We measured frequencies for 32 transitions of the O₂ A-band (b¹Σ⁺_g ← X³Σ^-_u) using the frequency-stabilized cavity ring-down spectrometer located at NIST, Gaithersburg, MD. Absolute spectral positions were calibrated in terms of the hyperfine components of the D₁ (12985.19 cm^-1) and D₂ (13042.90 cm^-1) atomic transitions of ³⁹K. A continuous- wave external cavity diode laser synchronously probed the ring-down cavity and ³⁹K absorption cell. The latter system was arranged in a double-pass configuration and yielded Doppler-free saturation spectra of ³⁹K with a resolution of 300 kHz. Using this calibration, the ring-down cavity's free-spectral range (used for interpolation and extrapolation from the ³⁹K transition reference points) was determined to within 80 Hz. The combined uncertainty in the O₂ A-band transition frequencies was < 1 MHz, which is more than 40 times lower than previously reported uncertainties for the O₂ A-band. Excited state molecular constants were calculated from these results and compared with previously determined values. These new transition frequencies should serve as a convenient secondary calibration standard in the 760 nm to 770 nm wavelength region.
DE: 0350 Pressure, density, and temperature
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting