Determination of Self-, Air-, and Oxygen-Broadening Coefficients of Pure Rotational Absorption Lines of Ozone and of Their Temperature Dependencies

Abstract

Room temperature measurements of self-, air-, and oxygen-broadening coefficients are reported for 101 pure rotational absorption lines for 16O3 covering a range of 7≤J″≤34 and 3≤K−1″≤11 in the spectral region 50 to 90 cm−. In addition, the temperature dependence of the coefficients has been determined for most of these lines. A total of 14 high-resolution Fourier transform far-IR spectra (0.004 cm− resolution) of ozone/air/dioxygen mixtures were recorded at various temperatures (212, 252, and 296 K). The broadening coefficients and corresponding temperature exponents were deduced by analyzing all of the 14 spectra simultaneously for each absorption line using a nonlinear least-squares fitting technique. Several sources of systematic errors were taken into account: the values of the partial pressures of the species involved, the value of the total optical path length, the sample temperature, thermal emission from sources other than the spectrometer source (e.g., sample emission), the effect of convolution with the instrument function, and intensity contributions from weak and neighbouring absorption lines. The variation of the determined broadening coefficients and temperature exponents with the rotational quantum numbers J″ and K−1″ has been examined. Furthermore the determined pressure-broadening parameters have been compared to the data reported in the 2000 edition of the HITRAN compilation.