Line Broadening in the Fundamental Band of CO in CO–He and CO–Ar Mixtures

Infrared HCN Lineshapes as a Test of Galatry and Speed-Dependent Voigt Profiles

“…From a careful examination of reported data, it is interesting to note that this high-pressure regime occurs for collisional widths larger than only a few Doppler widths. Dealing with CO lineshapes, the sole exception seems to be the He-induced relaxation case for which the Galatry profile leads to a linear pressure dependence of β (41,55), in agreement with our own observations on the He-HCN system.…”

“…To our knowledge, concerned molecules are so far C 2 H 2 (47-50), CO 2 (51), CH 3 F (52), and HF (53), but the most documented case is the infrared spectrum of CO (16,17,41,(54)(55)(56). In the low-pressure regime, the optical diffusion rate β evolves linearly with the gas pressure.…”

“…As explained in Refs. (54,55,57), b 0 and σ L J can be viewed as impact parameters characteristic of large efficiencies in relaxation and diffusion processes, respectively. If we discard the He case, all buffer gases, Ne, Ar, Kr, Xe, N 2 , HCN, and CH 3 Br, lead to optical radii b 0 larger than Lennard-Jones radii σ L J , b 0 getting quite large for the more massive buffer molecules.…”

Collisional line shifting and broadening in the fundamental P-branch of CO in Ar between 214 and 324K

“…Several groups have measured collisional broadening coefficients in the fundamental band with reported accuracies as small as ±0.5 · 10 À4 cm À1 /atm, or about ±0.1% (e.g. [5,8,9,10,11,12]), and there have been several studies at low and high temperatures (e.g. [6,7,8,10,12,13,14,15,16]).…”

The HITRAN 2004 molecular spectroscopic database

“…5) Helium-broadening parameters, their temperature dependence and pressure shift due to He were added. The broadening parameters were taken from Sinclair et al [173] HIT12 when available or algorithm from Ref. [176] 1370-40 0 0 HIT12 with many line positions fixed using HIT08,S Tyuterev et al [187] and empirical adjustments of HIT12 to properly fit KP spectra.…”