Foreign Gas Broadening Studies of the J' ←J = 1← 0 Rotational Line of CO by Frequency and Time Domain Techniques

Abstract

The collisional broadening of the J' J = 1 <-0 rotational line of carbon monoxide by the buffer gases He, Ne, Ar, Kr, CO, N 2 , 0 2 , and air has been studied at room temperature. Two different experimental techniques in time-and frequency-domain, respectively, were used. The obtained data are in good agreement. Time-domain investigations on the temperature dependence of the foreign gas broadening parameters are also presented.

A Comparison of Lineshape Models in the Analysis of Modulated and Natural Rotational Line Profiles: Application to the Pressure Broadening of OCS and CO

“…In addition, it should be noted that VP, GP, and RP give very similar results; this is due to the fact that the greatest part of the points are at a sufficient high pressure to be well described by Voigt profile. Finally, as expected, the natural line profile analysis of the J = 9 ← 8 transition of O 13 CS gives self-broadening coefficients with larger standard errors.…”

“…By comparing different models and using the J = 9 ← 8 transitions of O 12 CS and O 13 CS as an example, we would like to show that the frequency modulation technique not only provides results in good agreement with natural line profile analysis, but also allows measurements with fair accuracy for weak transitions, for which the amplitude modulation technique gives large experimental uncertainties because of the poor signal-to-noise ratio.…”

“…In order to compare natural and modulated line profiles, we then switched to the J = 9 ← 8 transition of O 13 CS, whose absorption is less than 1%. It has been recorded with both frequency and amplitude modulation techniques, which still gives a signalto-noise ratio high enough for lineshape analysis.…”

Line Broadening and Shifting Studies of the J=5←4 Transition of Carbon Monoxide Perturbed by CO, N2, and O2

“…The procedure to investigate the pressure dependence of the lineshape was basically the same as described in (26). The studies of self-broadened linewidths were carried out at pressures of the pure gas ranging within 0.2-5 Torr.…”

Pressure Self-shift of the J = 1 ← 0 Line of Carbon Monoxide

“…method described in (5,6). Briefly, the spectral line was digitally recorded with step-by-step frequency tuning of the radiation source.…”