Measurements and Calculations of the Halfwidth of Two Rotational Transitions of Water Vapor Perturbed by N2, O2, and Air

Half-width temperature dependence of nitrogen broadened lines in the ν2 band of H2O

“…High-resolution measurements of the H 2 O doublets at 2115 and 2136 cm À1 have been performed with a diode laser spectrometer at temperatures from 446 to 856 K [16]. The reported halfwidth for the 2115 cm À1 line at room temperature (0.045(3) cm À1 /atm) and the temperature exponent for this line N (T ¼ 466 KÞ ¼ 0:33 (30) coincide with our measurements within the experimental accuracy.…”

“…Bauer et al [2][3][4][5][6] have studied the temperature dependence of the water vapor line shape in the regions around 183 and 380 GHz. Goyette and DeLucia [7] have measured the half-width of the microwave (MW) line at 183.3 GHz (rotational transition [3 1 3] [2 2 0] where we use the notation [J K a K c ] for a rotational level) in a very wide temperature interval between 80 and 600 K. Recently Colmont et al [16] measured the temperature dependence between 300 and 393 K for two MW lines at 203.4 and 325.1 GHz. Hartmann et al [17] have studied two doublets of the m 2 band of water vapor broadened by O 2 , N 2 and Ar in the 400-900 K temperature range.…”

Relaxation and Lineshape of the 500.4-GHz Line of Ozone Perturbed by N2 and O2

“…As expected, all these rates exhibit linear behaviors versus the buffer gas pressure. However narrowing rates ⌫ 2 and ␤ present some scattering at the higher pressures; as already mentioned for experiments in the infrared domain (17), this effect is probably related to baseline effects, namely the curvature of the spectrometer mode. The corresponding straight lines, obtained by weighted linear least-squares fitting, have been drawn and the related relaxation coefficients, defined by…”

“…A detailed description of the experimental setup used along the recording of spectra has been given previously (17). Here we only recall that an important limitation on the accuracy of the linewidth measurements is the baseline curvatures caused by the standing waves in the cell.…”

“…Recently we have reported results on pressure broadening effects for two millimeter lines of water (17), and for the J ϭ 3 4 2 rotational transition of CO (18,19). We present here measurements performed on the J ϭ 34 2,32 4 34 1,33 rotational line of ozone located at 500.…”