Determining tunable diode laser spectrometer performance through measurement of N(2)0 line intensities and widths at 7.8 microm.
The N(2)O R(8) doublet of the 11(1)0-01(1)0 band at 7.8 microm was measured by a tunable diode laser spectrometer designed and assembled at Perkin-Elmer. The spectra were digitized and least-squares fitted to Voigt line profiles to yield N(2)O line parameters and a quantitative measure of instrument performance. Scans at various pressures produced consistent spectral line values: S(0) = (0.1746 +/- 0.0043)cm(-2)/atm at 300 K, alpha(L)(N(2)O - N(2)O) = (0.1066 +/- 0.0041)cm(-1)/atm,alpha(D) = (1.194 +/- 0.018) x 10(-3) cm(-1), andalpha(L)(N(2)O - N(2)) = (0.0870 +/- 0.0015)cm(-1)atm. A spectrum with several levels of synthetic noise added was used to verify the fitting algorithm's stability. The spectrometer was shown to possess an excellent SNR (e.g., 900:1) and wave number precision (</=2 X 10(-4 cm-1)) for spectral scans with 0.1-sec time constant.
Chen
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Niple
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Poultney
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