Effect of ΔJ= 4 transitions on the far infra-red normalised lineshapes of O2, CO2 and (CN)2 gases

Abstract

Fourier transforms of the far infra-red pressure induced absorption bands in O₂, CO₂, and (CN)₂ gases are compared with theoretical expressions derived from ΔJ= 2 and ΔJ= 4 (quadrupole and hexadecapole induced) line intensities. Satisfactory matching of theoretical and experimental normalised lineshapes displayed through the corresponding time domain functions, is obtained for O₂ and CO₂, but not for (CN)₂. Reasons for these findings are discussed.