Collisional Broadening of Vibrational-Rotational CO2 Lines by Buffer Gases

Abstract

Unsaturated absorption coefficients in pure CO2 and binary mixtures of CO2 with buffer gases Mj (He, Ar, Kr, Xe, N2, O2, CO, N2O, 13C16O2) were measured with a tunable CO2 laser at the central frequencies of the R(8), R(22), R(34), P(8), P(22), and P(36) CO2 spectral lines of the 1000–0001 transition at a temperature of 300–700 K. A technique is described and the coefficients of self-broadening and broadening of CO2 spectral lines by a buffer gas Mj are calculated. It is shown that the efficiency of the CO2 interaction with diatomic and triatomic molecules is determined by the electric moment; in the case of inert gases, the mass factor plays the major role. It is ascertained that the temperature dependences of the collisional broadening of CO2 spectral lines can be highly accurately approximated by power functions with two different exponents.