ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Experimental and theoretical results on the influence of line mixing on the shape of infrared CO2 Q branches of importance for atmospheric applications are presented. Two Q branches of Σ←Π symmetry, which lie near 618 and 720 cm−1 and belong to the 1000II←0110I and 1000I←0110I bands, have been studied for many conditions of temperature (200–300 K), total pressure (0.5–10 atm), and mixture (with He, Ar, O2, and N2). The theoretical approach used is based on the Energy Corrected Sudden approximation; its parameters have been deduced from both line-broadening data and measured absorption by the Q branches. Comparisons between experimental and computed spectra demonstrate the quality of the model, regardless of the conditions. Detailed analysis of the influences of the Q-lines spectral spacing, temperature, total pressure, and collision partner are presented. They show that significantly larger line-mixing effects are obtained when CO2–He is considered with respect to CO2–(Ar,O2,N2). This is analyzed in terms of the relative contributions of the short- and midrange interaction forces and of propensity rules resulting from the coupling of angular momenta. © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.474789
