Rotational collisional narrowing in an infrared CO2Qbranch studied with a tunablehyphen;diode laser

摘要

Rotational collisional narrowing, or line mixing, has been observed in the infrared absorption spectrum of theQbranch of the (1110,0310)IIndash;thinsp;0000 band of CO2at 1932.47 cmminus;1using a tunable diode laser. Spectra were recorded at pressures ranging from 100 to 745 Torr both inside theQbranch and below the band origin. The observed absorption coefficients below the band origin were up to 80percnt; less than those calculated using an isolated Lorentz line approximation. A simple fitting law for the statehyphen;tohyphen;state rotationally inelastic rate constants is determined using the known line broadening coefficients. A calculation of line mixing using these rates agrees with the observed absorption coefficients to within several percent.