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

Self-broadened 12C16O line shapes in the v=2←0 band

“…These effects have been observed for CO line shapes in a number of high-resolution studies [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], motivated in part by the need to monitor this species accurately in the earth and planetary atmospheres. Most of the CO line shape measurements have been reported for the v ¼ 1 0 fundamental band in a variety of buffer gases using a tunable differencefrequency laser [13][14][15][16][17][18][19][20] or diode laser [21,22].…”

“…Most of the CO line shape measurements have been reported for the v ¼ 1 0 fundamental band in a variety of buffer gases using a tunable differencefrequency laser [13][14][15][16][17][18][19][20] or diode laser [21,22]. In addition, microwave data for pure rotational lines [23][24][25][26] as well as Fourier-transform [27][28][29] and diode laser [30] spectra of the overtones have exhibited non-Voigt profiles.…”

“…Generally, these fits could be improved to within the experimental noise level by incorporating Dicke narrowing using either the soft-collision model of Galatry [2] or the hard-collision model of Rautian and SobelÕman [3] with an adjustable narrowing parameter, b. However, it has been noted [13][14][15][16][17][18][19][20][21][22][23][24][25] that the fitted b is non-linear in pressure and larger than the value predicted by diffusion [1][2][3] …”

“…On the other hand, no Dicke narrowing or speeddependent broadening distortions of the Voigt profile were observed in recent high-resolution FTS [31][32][33][34] and diode laser [35] spectra of self-broadened CO. This may be due to insufficient sensitivity since Dicke narrowing had been reported for other FTS [27][28][29] and diode laser [30] spectra, and speed-dependent effects are readily apparent for broadening by N 2 [13][14][15][16][17][18][19]21,23,24,27], which has the same mass as CO.…”

Shifting and broadening parameters of the water vapor 183-GHz line (313–220) by H2O, O2, N2, CO2, H2, He, Ne, Ar, and Kr at room temperature

“…The advantage of the RAD spectrometer is recording the true absorption profile of a line by means of amplitude modulation with a signal-to-noise ratio (SNR) on the order of 1000, as demonstrated earlier in a study of the rotational spectrum and broadening and shift parameters of O 2 and CO molecules [3][4][5]. A water sample was obtained from a double-distilled water source.…”