Dicke narrowing, speed dependence and line mixing of self-broadened CO2 absorption lines in the 30013 — 00001 band. Measurements and line shape testing
V.A. Kapitanov1, K.Yu. Osipov1, A.E. Protasevich1, Yu.N. Ponomarev1, Ya.Ya. Ponurovskii2
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
2Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow, Russia
Keywords: laser spectrometer, absorption line profile, pressure dependence, CO molecule
Abstract
Experimental results are presented for self-broadening and shift of six isolated absorption lines of CO2 versus pressure in the 1.6 mm spectral range at a room temperature. The measurements were carried out at a high-sensitivity high-resolution diode laser spectrometer with a signal-to-noise ratio of 3000 to 7000. To describe the experimental spectra, five theoretical line profile models VP, RP, qSDRP, qSDVP, and qSDVP + LM were used. A strong influence of weak closely spaced lines on the parameters retrieved (intensity and collisional broadening coefficient) of strong lines was found, as well as nonlinear pressure dependence of narrowing parameter for RP and qSDRP line profile models. The linear pressure dependence of the parameters retrieved for qSDVP + LM line profile is shown in the range from 0.001 to 1 atm.
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