Collision-induced absorption of infrared radiation by N2, O2 and CO2

Abstract

The collision-induced absorption of the symmetric vibration of CO 2 has been observed in the pure gas at densities from 20.0 to 40.0 amagat and at temperatures of 273, 298, and 323 K using infrared techniques. From the integrated intensities of the bands and using the (exp −4) model of van Kranendonk, it is possible to deduce a value for the first derivative of the quadrupole moment with respect to the vibrational coordinate. For CO 2 the contribution from quadrupole distortion to the binary absorption coefficient is reported for several temperatures. The (exp −4) model of van Kranendonk is used to calculate the binary absorption coefficients for the fundamental vibrational bands of N 2 and O 2 at temperatures from 70 to 340 K. The parameters λ and p /σ describing the magnitude and range of the short-range collision-induced dipole moments were determined using the known experimental absorption coefficients. The contributions from atomic distortion and quadrupole distortion to the binary absorption coefficient are calculated for N 2 and O 2 .